Ollys, heres a post I made a while a go:
Advise please the use of a small inflatable as 1st boat
I ve had a Suzy 2, Honda 2hp 4 stroke and a Yamaha Malta 3hp. Had them all on a bombard 2m SIB and now got an Avon R280 air deck.
With the 2hp Suzuki on the AX2 it just planed with a light person in it, 10 knots gps. But you have to remember the Ax2 is tiny and very light, this was also on flat water. You can have a lot of fun with a 5hp+ on an air deck, unless your 20 stone in which case it won't plane.
Heres an AX2, tiny!: