Will you be trailering it or assembling & disassembling it with each use?
Do you drive a pickup truck or a car?
Do you have launching wheels?
I believe that the mark IIs are rated for a maximum of 40 hp. Staying within that maximum, I'd recommend getting the most powerful outboard that you can manage. You can always use less throttle when not needed.
I'd also highly recommend getting launching wheels regardless of whether you have a trailer. If you don't have a trailer, but have a pickup truck, you can get one of of those portable folding truck bed hoists that swivel. They would allow you to lower the outboard directly onto the transom & vice versa without risking injury to your back.