I did a 12# spatchcocked turkey for Thanksgiving on my PG500.  Zone 4, 325 degrees.  I also put it up on about a 3" aluminum roasting pan to catch the drippings. ( Setup below ).  It was mostly done in the breast and thighs in 1 1/2 hours.   160 breast, 175-180 thighs.  BUT when I probed deeply with my thermapen, the breast was only 145-150 and the bottom side of the thighs were only 145-150.  My first thought is it is due to the top-down heat.  But other factors I have to consider are 1) the large pan blocking some airflow and 2) I only let the turkey acclimate towards room temperature out of the refrigerator for about 30 min.  Does anyone know what causes this ?  Until I come up with a better plan, I think I'll have to start the bird breast-side down for maybe 45 min. because I want to catch the drippings. 

I would say pan is deflecting some of the radiant heat that is coming off of the drip pan. How about raising turkey up some away from pan so heat will circulate more? Looks like you have a second shelve.

Mudflap

I did a turkey breat only on the PG 1000. Used a pan with an adjustable roasting rack like this one. https://www.amazon.com/Norpro-Adjustable-Roasting-Rack/dp/B011CN4QYE/ref=asc_df_B011CN4QYE/?tag=hyprod-20&linkCode=df0&hvadid=242040834902&hvpos=1o2&hvnetw=g&hvrand=10059747942120824969&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9019334&hvtargid=pla-486767310850&psc=1

I cooked evenly top to bottom, but not as much browning on the bottom.

Was there water in that drip pan?

Lose the drip pan.  You may not need drippings for gravy.  Make turkey stock from the cast-off parts (the neck cut into four sections, the giblets, fat or skin that you trimmed away and such).  You can find recipes on the Internet.

• Brown them in a well-oiled pan.
• Cover them with water.
• Add onions, celery, carrots, garlic, wine, a piece of parmesan cheese rind, peppercorns, bay leaves…  Brainstorm additional ingredients.
• Low simmer it for a few hours.
• After you strain it, it’s turkey stock.
• Slowly add it to a flour/butter roux and it’s gravy.

Lose the drip pan.  You may not need drippings for gravy.  Make turkey stock from the cast-off parts (the neck cut into four sections, the giblets, fat or skin that you trimmed away and such).  You can find recipes on the Internet.

Agreed.  If using a drip pan under the turkey the top of the pan needs to be 2" or so above the bottom of the turkey.  The liquid in the pan and the turkey being so far in the pan did not let the heat get to the bottom of the turkey.   

Was there water in that drip pan?

Yes - liquids.  I put in the fixings for the stock:  2 cups chicken broth, 1 cup water, 1 large sweet onion, 3 stalks celery, 3 stalks onions.  I made it into gravy, similar to your recipe.  I like this gravy - it has a nice, subtle smoky flavor.  Not strong, but it does pick up a bit of smoke.

Re: "Lose the drip pan".  I take it you think the problem is airflow around the turkey.  I can try it without the drip pan next time.  I'm also thinking about trying it on the shelf in zone 3 - if it fits.  And then leave the drip pan down on the grate of zone 4.  Will of course adjust temperatures in zone 4 to produce desired temperature in zone 3.

Lose the drip pan.  You may not need drippings for gravy.  Make turkey stock from the cast-off parts (the neck cut into four sections, the giblets, fat or skin that you trimmed away and such).  You can find recipes on the Internet.

Agreed.  If using a drip pan under the turkey the top of the pan needs to be 2" or so above the bottom of the turkey.  The liquid in the pan and the turkey being so far in the pan did not let the heat get to the bottom of the turkey.   

Thanks - you're reinforcing pmillen's thoughts about airflow around the bottom of the turkey.  I can probably find a way to 1) use a shallower pan and 2) put the turkey 3-4 inches above it.

Re: "Lose the drip pan".  I take it you think the problem is airflow around the turkey.

Not necessarily air flow.  The liquid was a heat sink.  It was sucking up the heat your pellets were making and it was never above ~212°, so you had a cold spot under the bird whose surface you were trying to heat to 325°.
 
I think liquid in most pits is overrated.  It's especially true in a quality pellet pit.  You were just putting water vapor into your neighborhood.

My 

Re: "Lose the drip pan".  I take it you think the problem is airflow around the turkey.

Not necessarily air flow.  The liquid was a heat sink.  It was sucking up the heat your pellets were making and it was never above ~212°, so you had a cold spot under the bird whose surface you were trying to heat to 325°.
 
I think liquid in most pits is overrated.  It's especially true in a quality pellet pit.  You were just putting water vapor into your neighborhood.

My 

1.  Thanks for the heat sink explanation - that makes a lot of sense.  Especially as close as my bird was to the liquids.
2.  I was not trying to introduce liquid into the pit to produce water vapor - I wanted to produce fixings for gravy   But I do understand the dilemma here - need to find a way to keep the gravy fixings ( with a lot of liquid ) from cooling the bottom of the bird.  Or give up the fixings prepared on the smoker. ( My wife doesn't like the smoke-flavored gravy anyway ).

Thanks !

Re: "Lose the drip pan".  I take it you think the problem is airflow around the turkey.

Not necessarily air flow.  The liquid was a heat sink.  It was sucking up the heat your pellets were making and it was never above ~212°, so you had a cold spot under the bird whose surface you were trying to heat to 325°.
 
I think liquid in most pits is overrated.  It's especially true in a quality pellet pit.  You were just putting water vapor into your neighborhood.

My 

1.  Thanks for the heat sink explanation - that makes a lot of sense.  Especially as close as my bird was to the liquids.
2.  I was not trying to introduce liquid into the pit to produce water vapor - I wanted to produce fixings for gravy   But I do understand the dilemma here - need to find a way to keep the gravy fixings ( with a lot of liquid ) from cooling the bottom of the bird.  Or give up the fixings prepared on the smoker. ( My wife doesn't like the smoke-flavored gravy anyway ).

Thanks !

I have had success when making turkey/chickens by removing the drip tray and putting a catch pan in the warming drawer to collect the drippings.   I just try to make sure to center the birds over the pan so as to not make a mess.

I have had success when making turkey/chickens by removing the drip tray and putting a catch pan in the warming drawer to collect the drippings.   I just try to make sure to center the birds over the pan so as to not make a mess.

A great idea for the PG500/1000 series pits.  Admirable.

I have had success when making turkey/chickens by removing the drip tray and putting a catch pan in the warming drawer to collect the drippings.   I just try to make sure to center the birds over the pan so as to not make a mess.

A great idea for the PG500/1000 series pits.  Admirable.

I agree, that's actually a great idea. 

 I was going to suggest that if a water/drip tray was desired, I'd make sure I had my turkey raised up above it by at least 3 or 4 inches.      I tend to like to get my food up as far in the indirect area as i can, where it's warmer...    Many things I cook directly on the upper shelf... a large turkey might not fit that well on the upper shelf though... So, having a drip/water tray down well below the main indirect cooking grate, could be just the solution.

  I have  like a 18 pound frozen Turkey , that I bought after Thanksgiving.  I'll likely cook it either on Christmas, or sometime between Christmas and New Year... I think I'm going to try the drip tray/pan thing down bellow when I cook that bird.   But then, I may wack the bird into pieces and cook breasts and dark meat all separately too, so well... there's lots of possibilities.