eh I would say that hucking a back is about the same as hucking a 360. But It's MUCH easier to just throw a slow, big backflip, technically. You just have to get over the inversion factor. You have to worry about the tucking up of the legs and the twisting of shoulders and such while doing the big 360.
So to all: yes, backflips are easier off big jumps while 3's are easier off smaller ones.
F*ck the blow, I'm addicted to snow.