No standard, really.I leave a centimetre free each end on toms, 1½ on bassdrums - but as you want as much free as possible, you´ll have to make an in-situ measure.Or use those Aquarians that are made for vintage shells, having hoops of a little wider diameter.Jon
i do have a set of the aquarians and they fit fine. i just happen to like the sound of remo coated ambassadors better. i can squeeze remos on the toms, but they don't fit the bass drum at all.