That Sprindrift 9 folding dinghy is certainly nice looking!
I would decide what type of boat you want. A go fast boat, or a practical dingy? We had RIB's on our bigger boats, but they were heavy--(12 1/2 foot RIB would carry 4 plus SCUBA gear or dogs--but required a 25 hp--with only 2 people a 15 hp would suffice. We carried both motors aboard)
For a slow cruising boat, a fast runabout is a very nice luxury, we used regularly. However on the C Dory, we tend to go fast on the bigger boat--and slow in the dinghy. We have owned several hard dinghys--and usually wanted them to be slow boats. (Sabot--a pram rowed or sailed, 2 hp motor max)--A 10 foot round chine early fiberglass boat with 4 hp and we still own a 9 foot Fatty Knees (never had a motor on it, but sail and 8 foot oars)--but it weighs 125 lbs!. I also owned a 6 foot and 8 foot flat bottom sharpie type of dinghy which my father and I made many years ago. The first 6 footer weight was only about 50 lbs, and was easily carried turtle style on your back. there was no thwart, just a very light 1/8" plywood sided and walled, floor board, which was about 2" thick and rested on frames. I made a centerboard well and sailing rig for the 8 footer, but it was also rowed. Neither of these were intended for motors.
The garvey is basically a flat bottomed punt--or square ended boat. The one you linked to has a bit of variable dead rise forward and will be fairly good in chop. But as the waves kick up, the boat will be a bit less seaworthy than a traditional bowed boat. Bateau.com also has a 10 foot Garvey which might be a better size; a bit lighter, and could be slightly modified to be a better boat for what you want. You could also make the Garvey in two pieces--but it will be heavier, and I would be reluctant to push it as hard with a motor.
I have really liked the stitch and glue construction. It is fast and easy. It also makes for a lighter boat. We did a 16 foot canoe, which weighed about 30 lbs (3mm high quality plywood, covered with glass). I have also owned fast boats 14 to 15 foot runabouts where the bottom was 1/4" ply and the sides were thinner--with a layer of glass, that can keep the weight down, and still have the strength necessary. A lot is in the engineering of the boat design.
Glen L also has a power Skiff in 12 & 14 feet stitch and glue--sort like a Hobie power skiff in its lines. That is a boat I like. You could make the 12 as a two part boat which nested, and a bit lighter than they plans call for. They take a 15 hp, but 5 to 8 will plane with a couple of people aboard.
If you were to put a clamp of nice varnished mahogany around the gunnel, it would be a beautiful skiff.