Speedmaster is a good size for that boat.
The 700 would need a 700 mount. A 5mm to .130 hex flex coupler.
On 12 cells I would recommend a 42 and 45mm 3/16 carbon prop to test with.
For odds and ends you will need some Velcro to hold your batteries down.
A steering rod.

Steven
www.OffshoreElectrics.com