Sawdust, thanks for the comments, I know this is not tradiotional but I'm trying. At this point I have nothing to sheet the walls with. Tin won't be here till Monday. Once it arrives I'll see if I have enough clearance to add the double plate to the top of the walls (I need to make sure the tin will hang ~ 1" below the top of the foundation. I like the idea of bracing the outer walls prior to installing the rafters (not sure what joists are).
Tonight's progress, I took the truss up and thought how in the he$$ was I going to ballance it on the two 2X6's. After pondering I resolved to disemble the truss and make it 24" tall instead of 18.5". The plan is to spread the 2X6's and place the truss in the center and screw the 2X6's to it (almost like what I currently have). I can still go back and add more 2X6X18's if needed.
Once I was done re-working the truss, I placed one end on the trailer and the other on the ground, stood it up and bounced my 250 lbs on the center, the only give I noticed was the trailer tire spring (this thing is stiff. Shorty, If the shop was 20' then both ends would be faceing down.