You made it confusing a bit - in your first post you want a board for 12-16 knots, and in post #3 you want to enjoy 3bf conditions. These are very different wind ranges.
Go for F133 and sail between 8.5 and 9m (freerace, 2 or 3 cams) to take advantage of the bigger board. You'll keep your 7.2 as a small sail for F133, it's better paired to a Futura than to an iS.
Btw, for a recreational sailor, a gap from 7.3 to 9.0 is perfectly acceptable (I use those sails on my iS122). A sail in between is a luxury, unless you have reasons for it (different boards, like Ken, etc).