Thanks BigDave83. I found a dimensional drawing online that seems to indicate that a side mounted stack on the hopper side will clear the hopper lid. For now, i'm going double side mounted. That Cookshack design is interesting and I may eventually gravitate to something like it. That's the nice thing about homemade, you can rework what you have done without voiding the warranty.
I finally got my sheet metal order today. Ugh! My supplier is cheap but the quality varies. My shipment contained a mixture of 11 and 12 gauge instead of all 11. Fortunately, his cutting was in error on the plus side.
My pellet hopper setup is now lost somewhere in the Fedex system. Though I have dimensional drawings in inches, my level of trust in things converted from metric is low. I will wait until the hopper arrives before cutting anything.