Word Bump's powerballs

[viva sinazcot]

Puisnies hath judgëd.

I'd figured out that the rainbow powerball boosts one letter to the top, but I was trying to learn whether it can be moved in order to store up for a second powerball. I found that the powerballs that haven't rainbowed yet, the ones that are solid red, or blue, or whatever, have different behaviours, very odd an difficult to understand. Is there a guide to what they're supposed to do, and is it random, or does it depend on colour? Also, can one accumulate two or three powerballs? How is that done?

Good luck ~.