Some club members are flying the Mach 2 with 36 size engines and they seem to be the perfect match. Unless your a real speed demon, a 46 would be over-kill.
I've heard of guy's using 60's in these things for 3-D and to hover but we are doing combat and towing streamers.

Don't glue the tail on cuz you can re-use it on the next new one and the next new one after, that if it doesn't get chewed up or brake in the crash , I'm speeking from experience.