Green is going to be brighter than the other colors, that is just the way it is. Get a green front and some other color for the rear if you go multicolor. If the rears are brighter than the front it will not be as good as it can be.
I have a BIG BOLD set of Meps on my G22, and love them. I have green for all three vials and no regrets at all. I have tried the multicolor setups and the three of the same setups, I don't find any advantage to the multicolor setups other than they look "cool". Aquisition is just as easy, and you really can't hold the gun so that you have the front dot outside the rear dots without KNOWING something is drastically wrong. The gun will feel funny for sure and the sights will appear totally wrong, it just isn't worth worrying about.
If there is one problem with my Meps I would say they are too bright, I would prefer they were a little less bright. These things are BRIGHT! With time I will get my wish as they all dim with age, but being brighter to start they should last longer than a dimmer set would have.
Hope this helps.