All Rainbow are good but
Crit and Weakness makes the strongest team
You have Colchicum, Kugaisou for a good start 45%
The easiest thing to choose is Japanese Apricot to bring you to 75% and save your RG stones.
use your Lotus Bride and add 5* Cymbidium with no RG and use her until you get a rainbow 1.65.
That would make a pretty strong team now.

Look to get Weakness support (Pygmy/Sensitive Plant/Fennel yukata)
and as you get more crit girls you can use Ume with Rainbow Rose when the day comes you get her.