[pfapfap]

I start with 10x T20, 8x T100, 2x T500. As people do rebuys, I either give them one of these 20-stacks (great in racks!), a stack of 20 T100s, and four T500s. When those run dry, I switch to 1000.

For coloring up, I do it either on breaks or when I've busted (yes, I run and play... I set up my structure to have a game I wanted to play, so I'm playing it, darnit)...

If someone just has a massive pile of chips, I'll either slide him a rack and have him load it up, or slip behind him and rack for him if he's the type to take forever with it. Otherwise, I wait until the chips are truly no longer needed.

If someone has three stacks of T20, that's T1200, so I grab three T100 and one T500 from the stack (cuz I'm out by then) and give 'em two T1000 chips. Continue as necessary. It's helpful if you get someone to start "buying up" all the small denomination chips during the round leading to a color-up, but most can't figure that concept out, so I don't sweat it.

I'm making it seem more complicated than it is. Not sure really why you're having trouble or what benefit there is to getting the big chips in play as soon as possible. If anything, it slows down action when you have chips too big for the blinds at the time. Just do it when you have to.

...and if you have 50 people, eventually you're going to realize the benefit of (a) fewer denominations; (b) more chips overall; and (c) racks. It is VERY EASY AND FAST to load/take a rack of T100 and say, "okay, that's T10k, here you go." It's also much better for initial chip distribution and overall storage, not to mention moving people between tables.