To those who were responsive to my many questions, thanks! YOU MADE THE DIFFERENCE. (to those who used my queries for other reasons...you already have your reward.)
I have completed the Project Barn. It has a 30x40x12 (4/12 roof) enclosed radiant/insulated shell, 7 thermal windows, radiant floors with two layers of radiant/poly sheeting and two layers of vapor barriers in 5 1/2 inches of rebar concrete. The exterior is 26 guage Mueller copper roof, and off-beige walls. One interior side has 25 x 11 foot shelving, and the other side is peg board. As a bonus, I had the iron workers put up a 20 foot I-beam at the 20 foot mark, and I installed a 3 ton trolley chain lift. The roof has two barn-style ridge vents, and I installed 3 60 inch industrial bladed fans. I cannot see how to insert photos, sorry