How do you determine the size of a prop for a given engine?

For instance, I have the Alpha trainer and want to get all I can from it later on. Plus, the 3 blade prop that the Evolution engine uses costs $13.

I've been told to use a 10x6 2 blade prop, I'm getting a 2" spinner.

Also, do I need to remove the flywheel? I read the review of the Evolution engine and it said that the packaged one comes with a standard thrust plate. Mine didn't.


Any help?

Thanks!

Michael