If he has or can easily obtain constant current drivers, then that's probably the easiest thing to do. However, if he hasn't got them available, it may prove easier to use a scheme he can build out of simple and widely available components. Controlling brightness of LED's that behave differently depending on color may present overhead he would wish to avoid. After all, it's just another parameter he has to track. If the cathode driver sinks the required current, then all he has to do is switch the anode.

Chico has shown that he's a serious hobbyist. He's probably not willing to wait a week or longer for the chance to try a component combination he hasn't yet proven. If he finds the constant-current drive meets his need, whether it's provided with an integrated constant-current driver or a discrete one, he then knows he has a workable approach.

BTW, I don't think controlling the brightness was his goal. His problem was that the brightness of different color LED's didn't match well at the same current. That would necessitate a different current sink for each color, don't you agree? Once he has a good color-brightness match, he can determine whether he wants to use PWM rather than controlled current to effect his brightness management.

RE