On a practical basis, what do you do when your unit bet is $20 and your betting ramp calls for 3 units? Do you bet 2 green and 2 red chips? 12 red chips? 2 green chips only?

I don't often see players mixing chips of different denominations and I'm wondering if this is a red flag. Is it?

By the way, my unit bet IS $20: I bet 1@TC=1, 2@TC=2, 3@TC=3, 4@TC=4. I bet table minimum at -1