Re: S2 7.9
A few other points to consider for an S2 7.9 purchase. The boat plus trailer will weigh around 6,000 pounds. You'll need a decent-sized vehicle to tow it.
On what to do when the wind pipes up: Sounds like you handled this well. You are right that boats & crew should always be ready for these conditions. My own way of handling these situations is to, first, drop the head sail, and sail under main alone close to the shelter of the marina. Only then do I start the motor and drop the main. The reason for this is that in waves, most boats will handle better under sail than by motoring. Outboard motors in particular are not so good in waves.
A 7.9 that has been converted from inboard to outboard also needs to have the interior ballast adjusted (moved and weight added). I don't know how to do that.
The nearly 7 kt speed I got was in unusual conditions - surfing down following waves in 15 to 17 kts of wind on a broad reach. Made it from the NW corner of Pelee (I love that place) to Sandusky Bay in three hours - that's an easy 20 miles. It was way fun. It's way less fun when those sorts of waves are on the nose - tough on both people and equipment.