I've actively raced our J/29 for many years, including long races with deliveries before and after. We never leave a motor on the stern for racing.
We do the two-motor solution. The delivery motor is a Tohatsu 8 HP, weighs about 95 lbs. A pain to get on and off, but does a great job of moving the boat, including pushing into 20+ Knot headwinds and waves.
The regatta motor is a 3.5 HP Tohatsu - we call it the one-hander since it can be handled easily. For in and out of the slip, it works very well, and it's pretty easy to maneuver on and off the boat. In general, we sail in and out if there's any breeze, so wrestling with it in any waves isn't a problem.
We have an occasional condition of big winds that make it impossible to get to our slip (straight upwind, narrow fariway, so not sailable), and the 3.5 does fine pushing us into the slip. We sail into the harbor and hang off a dock to put the motor on. I wouldn't want to depend on it outside the harbor in any waves, though.
Boat is for sale, BTW, with both motors and good sails, if anyone wants a great boat.
As long as B is overlapped inside and is on the same tack A has to give B room.
Don't sound right to me. Now you have a situation where the overlap was acquired in the zone.
Rule 18.2.c says it 'ceases to apply' when the boat with mark room passes head to wind. Not that it's off until they're on the same tack again. I think once you tack, you're out of mark room and subject to the other rules.