[simplechamp]

If you gear both setups for the same speed the lower kv, higher voltage (1700kv on 6S for example) setup will draw less current and you should be able to boost your runtimes a bit and stay cooler.

The 1700kv will do best on 5-6S, the 2250kv best on 4S. If you decide to change later the motors could still be made to work, but it wouldn't be optimal and gearing might be limited.