I would build your roof in place, rather then on the ground and lifting up(I think that was your plan?)
Plan is to build the frame in the yard, lift one end up and slide it into place. Once it is anchored, then I can slide the plywood and metal roofing over that in 2 sections anchoring those as I get each in place. I think that will work. No way could I lift it with the plywood attached.
I'm also now doing a flat roof as I had nightmares about it not fitting properly last night. LOL We rarely get a lot of snow so I'm not concerned about snow weight. I will need to cut out one more ventilation window on the south side, no biggie.