As had written in reply to comment, the mounting of the engine was done empirically. I purchased an adjustable engine mount and scribed bolt hole locations roughly over the area of the existing factory bracket mounting holes. The factory bracket mounting holes I had actually created an engine mount for of my own design (out of oak) dating back to approximately 2003. The holes were in a 3-over-3 pattern with the nuts set into the fibre glass of the transom. Had originally used these until my original engine mount rotted away after many years. Instead of making a new one, I had opted for an adjustable aluminum mount (pictured).
This allowed raising and lowering of the motor…not because the shaft was too short — a standard small outboard would work fine. The main thing was to get the engine out of the water during sailing to reduce drag.
Living on the Chesapeake Bay, there are shallows and gunk holes all over the place here. It was a great location for sailing a small boat such as this one.
Now, my preference is rowing — something I took up over 36 years ago while in school. Less paraphernalia and gets me out on the water for just enough time that it does not take away from the family.