ahhh...you beat me to it!!
Well if your gonna play $20 buy in I would go with the following breakdowns
500pc
250- .25
225-$1
25- $5
You can give out a stack of 20- $1 or a combo of $1 and $5. If all the chips were in play that would be $412.50....quite a bit for "lower" cash stakes, about $40 each for 10 players. With this kind of a set worst case senario when all the chips are in would be buying chips from another player and keepin the money on the table!
You could also work it like this which may be a bit more functional
500pc
200- .25
250- $1
50-$5
for a total of $550 when all the chips are out and that is $55 per player for 10 players!
For the higher pc sets I would stick close to 200 .25 (20 per player for 10 players) then raise the $1's and $5's accordingly.
Hope this has helped some!
Good luck at your next cash game!!