Currently flying my twice-retored EU-1A that I bought already built at a swap meet. It was originally powered with OS61VF, correct OS pipe and 11x7.5 zinger, 14K RPM on 10% nitro. Performance was just ok at about 10Lbs. dry - really had to manage the inertia to get it to perform properly. Switched last year to a well used SHORT STROKE YS60FR on the correct MAC muffled pipe, 11x7.5 zinger. Performance was dramatically improved - really made the EU-!A come alive. I still have not tached the YS to see what RPM its making on the ground but it does unload nicely in the air - what a machine! I have a couple of Rossi 61s and will try one of those in another EU-1A that i am restoring - i hear they scream also. Of the engines you've listed, I would go with the Rossi - just make sure you get the correct pipe and take your time establishing the correct tuned length and you wont be disappointed. The EU-1A is a large airframe for a sixty - keep it light by using contest grade balsa for the sheeting and monokote on the wings and tail and dont forget the cut-outs in the outer portion of the wing to save weight.

I have not experimented with the long stroke engines in the EU-1A so am unable to comment on those.