weight considerations
Congrats on the new boat! And congrats on getting one with cocktail seating. Depending on how heavy an outboard we're talking about, it's probably best not to put it directly aft anyway, because too much weight on the fore/aft ends of a sailboat will lead to hobby-horsing. Your best bet might be to first determine which side of the boat the fuel tank is on, because the boat will probably list to the opposite side once the tank is half empty. So put the outboard on the fuel tank side, as far forward as your stern rail will permit. No matter where you put it, and no matter how small an outboard you purchase, it's going to look ugly for the first few days. If you're a cruiser, you'll get used to it. If you're a racer, you'll ultimately conclude that the only proper place for an outboard is in the bilge, as close to the keel bolts as possible. (I have a little 3.5 horse outboard on the rail of my 410, by the way, mounted just abaft the arch on the port side. You'd be amazed at how many dockside passers-by ask me how such a tiny engine can power such a big boat. Yikes. I give them a serious look and tell that it does okay unless I attempt to pull water skiers.)