How's your finances? A nice 4-stroke is certainly the engine of choice for the Corsair & by all means buy one -- a new one, rather than risk a used one.

However --as already noted, there is the issue of learning on something else. Because of their lower cost, flatter learning curve & somewhat greater resistance to crash damage, a 2-stroke is a better choice for your first engine. Unfortunately, with the Corsair a 2-stroke is esthetically not a great choice (wrong sound), so unless that doesn't matter, you are probably going to have to buy two engines.

A big 60-size trainer is a good choice, and a nice 75 - 90 size two stroke is also a good match (if you can keep your thumb away from the throttle). If you are a warbird guy, a big 2-stroke is a quite respectable esthetic match to the V-12 engined fighters like Spit, Mustang, P-39 etc, so it won't be wasted in the future.