I nailed together the first roof panel tonight after getting home from work. Each panel consists of 9 2x4's; 5 are cut to one length and the other 4 are cut to a different length. It takes a lot of nails to join these 2x4's into a panel! I was able to move the finished panel around and carefully moved it up onto my temporary loft by myself. (You can see it in the picture if you look carefully.) I plan to nail some blocks to the underside of the panels to hold them in approximate position and so they don't go sliding over the side of my SS.
I added a diagonal brace to one corner to stiffen up the frame. It worked great; the frame feels much more rigid. I plan to add one to the other corner also. If I had the plywood sheathing on, I'm sure it would be more rigid. I'm waiting to get the roof on before I put on the sheathing, because I'm not sure how high the sheathing will go on the sides. Once the roof is on, I'll butt the sheathing against the underside of the roof overhang.