Tofu/Kinky: what's the makeup you're looking at? Sometimes you can get the theatricals in larger sizes by going through a supplier. And fair warning, even the "only comes off with soap and water" stuff will still come off with abrasion, so expect to get it on the edges of your clothing and stuff; I think alcohol-activated makeup is the only one that's truly rub-resistant and that stuff's expensive as all get-out and a pain in the bum to get off.
Folks I know who did grey Noah (my brother and a friend this year at Kcon) used, I believe, one of the creme makeups and a powder set over it, followed by a spray sealer. It stays pretty well, but even that comes off a little with rubbing.
For what it's worth.
... my poor Lero is hanging upside-down off my bookcase looking at me. Oh, I miss having an excuse to carry him.