...If I was going to adopt something like your idea, I would make it 1x Green, 2x Blue and 5x Red. I think 2 green is excessive (for every game to always have 2 green), and 3 red is not enough.
I think some kind of setup where you have a variety of the colours makes for a better game...
I've only played a few times but have been using your recommended color ratios for the randomizer cards when rounding out the common Supply.
It's worked very well so far!