Finnz
You might want to try easing the CG back to 5 inches. It makes it a different plane. It's still completely manageable but will really do some more fun stuff.
I've had a TT54, YS63 and now a Saito72 in mine. Mine weights 5lbs 6oz with 2 oz of lead in the tail and a 5 cell battery pack at the trailling edge of the wing. The TT54 wasn't enough. The YS63 will jerk the plane around and the Saito 72 will too if you use enough nitro (30%heli). I have a YS53 and it's great but I don't think it would be enough. Based on how this plane flys with these engines I wouldn't use any 2stroke less than a very HOT 45 or hot 50+ with a Nelson tuned muffler. Right there your cost went close or past the YS or SAITO
The answer then is put a low cost 60 in it but it will gain weight