When I did tie dye before as a teen, or when I've dyed clothes, I have always used the dip dye method. So the new methods using squeeze bottles are a cool new idea. But they don't always prove to be the best method, certainly aren't always as even, if that's what you're going for.
So only use RIT for hot dip dye
For cold dye in a squeeze bottle, use Dharma Trading, Jacquard, Dylon, orTulip