Finally found the detail I was after in all those pics
View attachment 412176
EUR350 difference between 600 rafters and 400 rafters. Buttons in the grand scheme of things..
But if your calcs say 600 will be fine, go for it
Maybe cost in the extra for thicker battens and see how it settles out
Thats a saving for rafters. Still need to factor in more joists and more collars which takes it up to 750e.
