A couple of points to consider:
Assuming you are going for Precision Aerobatics (stunt), you can use your RC engine with the throttle wired open. You may want to eventually switch to a venturi for optimum performance.
You don't need a 4-2 break. Many fly steady RPM with a large diameter/low pitch prop.
Good luck whichever way you go, and welcome (back) to CL flying.

George