Boy you sure took on a project didn't ya....  With sheeting on such a delicate airframe, I would do a lot of pre bending with water and ammonia rubber banded to tubes to get the shape you need. I think it would be hard to keep everything straight if you don't.. This will be a fun one to watch, looking forward to your build... I love how they say "Giant scale" on the box, Rc planes have sure gotten a lot bigger over the years....