Both ways are fine, but if it is not really very square I do not think I would float it. Might be best to keep it as lined up as you can especially since it is a pretty large quilt!

I read this with interest. My grace frame and janome 1600p arrived yesterday. I have put up frame but not had chance to set machine up yet. I guess it is one of those personal preference things "to float or not to float"

i have same set up i only float my batting the top and bottom are on rollers

I float my tops but have a large gridded plastic (24"x39") that I use every time i advance the quilt to check and be sure I am keeping everything square.