...which brings me to this next point:
@Lototo, do I understand correctly that you mean to color-up T25 by introducing more T100, then color-up T100 by introducing more T500 etc?
This has two flaws:
1. If you feel the need to add more T100 at the first color-up, why didn't you have more from the start? Same question for adding T500 at the second color-up etc. There are usually less and less players for each color-up, meaning each player on average has more of each denom, so there is no need to add more.
2. It's a lot of extra, unnecessary work to add a bunch of T100 only to remove them a few levels later. Same for T500.
What I would do is to add T1000 at the first and T5000 at the later color-ups. At the first color-up in your scenario there's 10×12×T25 = 3000. So add 3×T1000, make change with the chips leader(s) for lower denoms so you can exchange everyone's T25. If you round up (which I recommend) you need another T1000.
At the second there's 10×12×T100=12000, so add 3×T5000, make change with the chips leaders, then color-up.
That way you don't do extra work, and you only need
120×T25
120×T100
50×T500
64×T1000 (or only 60 if you use T5000 for the first color-up as well. Yes, that would work)
Then add spares and add as many T5000 as you want to handle rebuys, deaper starting stacks, and of course color-ups.
My 3 cents