Thanks for the replies.
Right now I'm thinking that for this season I'll just keep the one I've got and pull it out of the well when it will be several days before I use it again, just lay it on its side (2 strokes don't mind that, right?).
Probably before that I'll try out some smaller hp engines just to see it, from someone in the club.
If I do decide to do the surgery it won't be as simple as Baldwin's - I'd be cutting into the area between the transom and the existing well. So I'd have to put up small bulkheads to keep a following sea from flooding into the actual boat, under the cockpit. Probably would have to cut off the back wall of the well and then extend the existing 3 sides back to the transom. A lot of scary work, there.