Tournaments have 12-20 players plus about 5 rebuys on average.
For your needs, I'd go with this:
T5000 starting stacks (20):
8 x T25
8 x T100
4 x T500
2 x T1000
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22 chips = T5000
T5000 re-buy stacks (8):
5 x T100
5 x T500
2 x T1000
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12 chips = T5000
560-chip set:
160 x T25
200 x T100
120 x T500
80 x T1000 (includes 24x for color-up of T25/T100 chips)
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560 total chips
With T5000 stacks, you don't need T5000 chips. The blinds will never be large enough to require that the T500 chips be exchanged, and with only 20 players and 8/8/4/2 stacks, using T5000 chips for re-buys presents logistical problems, since there aren't enough extra lower-denomination chips to make change.
Both issues can be alleviated by going to either larger T10K starting stacks, or using a 12/12/5/1 starting stacks -- but either solution requires buying more chips. You can put together a nice 600-chip tournament set (with five denominations) that services two 10-player tables with T10000 starting stacks (8/8/4/7, or 12/12/5/6 if single-table):
600-chip set (20 x T10K stacks):
160 x T25
160 x T100
80 x T500
160 x T1000 (includes 20x for color-up of T25/T100 chips)
40 x T5000 (includes 8x for T500 color-up and 32x for up to 16 re-buys or increasing starting stacks to T15K)
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600 total chips
The 'standard' tournament base colors in many venues are:
T5 - red
T25 - green
T100 - black
T500 - purple
T1000 - orange or yellow
T5000 - gray or pink
T10000 - blue
T25000 - dark red or dark green
Although there is a lot of variation in denomination colors above T1000.