3 top,
You hit on the principal difference between floats for everyday use, and emergency floats - the amount of flotation. For Sikorsky, we have a rule that the floats must allow safe water entry, they must keep the cabin fully dry, and they must allow full egress for all occupants. The aircraft can settle down where no self respecting pilot would lift it back off again, for instance.
You may find that the R-44 floats will allow takeoff at reduced weight and CG, and would be a problem for lift-off at full weight, mostly because of the amount of bouyancy.
[ 18 November 2001: Message edited by: Nick Lappos ]