For resining, I'd recommend a stand, even just a makeshift one. Resin sticks to everything and it's nice to have something that supports your pep while it dries. I'm sure you can improvise something quickly with stuff around your house too.
For example, I used mat board, coat hangers, planters, some old fencing, and blocks. Lots of stuff could work.
Should i cut out or take out the little paper visor before i resin?
I left my paper visor in while I resined, however, I never actually put resin on that area. I just left the paper visor in for support so the brim of the helmet wouldn't bow under its own weight while it dried. (it's easy to cut out after the rest of the helmet has hardened)
Also, I saw in your signature about wondering if you should fiberglass your helmet. I'd recommended fiberglassing the inside, even if it seems like an annoying task. It would be so sad if it got dented up or cracked after all that work!