Yeah, Rainbow is the best...no joke...it has become the prized strain in my garden. You will not be disappointed, and yeah, it does great in Hempy. I also use CES nutes, which come to find out is the guys that created Rainbow...so no wonder why it loves them so much.
UPDATE:
OK, wife is out of town with the nice camera...so sorry for the res of some of these pics.
Long story short I harvested the bt mother. 72 hrs of cold and dark.
Right before harvesting
I got many colas....biggest was 96 grams....several in the 70 gram range, 60 gram...