The OS 46FX is an EXCELLENT engine. The price you paid for the FX is exceptionally good, especially if it is new. That engine will fly any 40 size trainer out there with authority and it will also haul the Super Sportster quite well. The Super Sportster will make a decent second plane. It would not be one of my primary choices for a second plane, but it will work well.

I use 11x6 or 11x7 APC props on my 46 FXs for general sport flying. If you are going to put this engine in a trainer initially, I suggest using an 11x6 MAS prop initially. Once you get used to the plane and flying glow, change over to an APC 11x6 or 11x7 for added performance.