Welcome to Workshop @colin7 and thanks for making your first post. We hope you receive lots of great advice and inspiration for your projects from Workshop community members. Are you working on a pergola?
I'm sure that there will be members who can help with this topic. And for those community members who don't know, Suntuf is polycarbonate roof and wall sheeting.
I generally use Straight Snips
also try to avoid bending or creasing the sheets as it form a weak point in the polycarbonate, Predrill holes do not punch holes & avoid small tears.
Preplan sheet laying for single sheet fixings
Trying to fix ridge capping after you have fixed the sheets can also be challenging as you will be unable to walk on the sheets..