More information needed. As AlaskaFlyer states, pull-start with tiller-steer, or center-seating with steering wheel? What is the capacity of your davit and where is it located (stern, boat-deck, over a trunk cabin, etc.)?
How will you use the dinghy? How far? In Mexico, there are two schools of thought on dinghys. Latitude 38 have long advocated for the largest/fastest dinghy you can reasonably handle because it's your transportation. Makes sense if you're venturing some distance. There is a second school of thought for cruisers who just use a dink to go directly to shore - smaller OB that is lighter, less expensive to run, easier to secure, and less attractive to thieves. In Mag Bay, home to many sedentary cruisers, it's possible to trade a 3.3hp for a 9.9hp.
I lean KISS here, so a sit-on-tube and tiller OB is more my style. If price were no object, I'd go with an OC Tender - made in NZ and shipped in batches to the US to help reduce shipping costs. The 350 (12-feet) is a good size and will plane well with a 20hp.
https://octenders.co.nz/
Within the next year, I will be buying a new dinghy. Will likely go with an Achilles. I looked at Highfield, but I talked with a very knowledgeable person at Defender who carries several brands. In his opinion, Achilles has thicker and more durable hypalon. He was more enamored with fiberglass RIB than aluminum, and made a good argument that any knucklehead can fix a figerglass hull whereas Alum can turn into an Alka Selzer fizz-tablet if neglected. Fiberglass is quite a bit heavier though.
https://www.defender.com/product.jsp?id=6899982
https://www.defender.com/product.jsp?id=6062631#
As far as OBs, I'm a Yamaha guy. 15hp for a 310. 20hp for a 350.
Peter