Honeslty, I think you should go with the same colours you have now except with a few extra tones in between. Something like: deep red (0 to 29), scarlet (30 to 59), orange (60 to 79), yellow (80 to 99), lime (100 to 119), green (120+).
I like intervals of 20 once you get past about base 60, since there are more Pokémon with stats above that range and thus more distinctions to make. You could add a seventh interval at 140 with a dark green, if mine end too early. In general I think any blue shade is too complicated.