I just had an idea (a rare occurrence, but it does happen once in a while).
How about making a frame the size of the curb long enough to set on the slab forms (left and right sides).
You could just set it on the the slab forms and pour concrete in it right after pouring the slab.
Would probably want to put some rebar in it for additional support.
That way you could put the curb as close or as far from shed wall as you want
.

I thought that is what I was doing, but I have no spatial cognition, so I cant "see" what you are saying!

I guess I misunderstood what you were saying.

If you look at the 2nd photo in reply #26 you will see the 2nd 2x6 on top of the pad form.  I plan on pouring concrete behind it and then removing the 2x6's when it is dry!

OK, that is what I thought you meant.
What I was thinking was, instead of that, make a 4 sided frame (no top or bottom) the size of the curb that you could set on top of the slab forms and
position it anywhere you want the curb to be.

Now if you want the curb to be right against the shed wall, then forget everything I said. 

How wide is the pad? If its more than 8 ft. or so, you might consider a middle treated 2X4 so that you can screed half at a time. The center board will also act as an expansion joint to reduce cracking. A long, long time ago, I poured an 8' by 48' driveway 8' at a time using that technique. 

It is 18 x 20. That is exactly what I am doing.  Will run a 2by down the middle of the center 4x4, the 20 feet and only have to deal with 2, 9x20 sections (expansion joint too as you mention). The 1st section I think will be easier then the 2nd since the screeding can be done on either side when doing 1st section, but will have to pull the 2nd from the top down.  Hoping since there will be easy access the truck will back right up to the pad and there will be limited shoveling of mud and also limited screeding altogether.

How wide is the pad? If its more than 8 ft. or so, you might consider a middle treated 2X4 so that you can screed half at a time.

You might also consider putting a cross member parallel to the shed splitting the pad into four quadrants. Smaller segments are easier to screed and protect better against cracking. You can leave the outside form parallel to the shed off and back the truck between the forms, pour, screed, back up to the second section near the shed, pour, then nail on the form that you left off and pour the other two sections. It's probably not necessary, but when I did this type of pour, I put 12" pieces of rebar through the middle of all forms that have concrete on both sides to mitigate uneven settling. Something like this. (sorry for poor drawing, it's late)

Thank you!

We had snow at the very beginning of Feb.  Right about the time I made the last post, and I was thinking to myself that if we got that snow, I would not get back into this project till after Feb.  Pretty sure that is going to prove to be true.  It is such a non productive time of year for home chores in this part of the world.  Everything is wet, and you simply can't get into it.  About the only thing one can do is clean the house, and we all know that is kind of laughable...

It is simply a nasty time of year...although, starting next Monday it is supposed to be above 50° for 8 days in a row.  Maybe Dark Winter is finally over!

Were you able to get out of the mud after your chair fell in it?

I was certain that when I did the excavation, that I was real close front to back and side to side with the correct amount taken out.  Man, I will not be getting hired by any of the Pharos I guess.  I do not have a bubble that I could put on a string to level.  So the only way this math deficient worker new to get the fall for the slab was to level all the forms and then run a line (I did this on the far left), have to do the other 2 tomorrow.  I will now drop the line down 1.5 inches and then set the forms to the angle.  Then I will fill the sides and front and also fill in the pad. 

I am thinking of putting a 20' piece or rebar every 4 feet from top to bottom, then tie some hog wire to it and pour.

I was cruising along, had the pad leveled at 5", was drilling the holes in the forms to run the rebar through so I can lay the wire mesh and the battery dies on the cordless.  Oh well, always tomorrow! 

Ohh, and my math is so bad I was 6 boards short for the backer!

Looking good!!