Well, my starter motor was off a Land Rover ... but, that is way more than you will need. I would think that an automotive-type oughta do the trick.

I'm currently using the starter motor from a 500cc motorcycle. Been using that for about 15 years, I guess. That is plenty of power for the stuff I'm flying ... I don't have anything bigger than a 40cc four-stroke. I can't really advise as to specific starter motors that will suit your application.

The big Sullivan, on 24 volts, is a hefty bit of kit. Expensive, though.