Hi!
Please!! Forget any of the big .60 engines ...or .78 engines they are simply to heavy and powerful for the airplane .
Stick with a .40 -.46 twostroke and it will be just fine.
Honest... for a second airplane I would choose something else ...a low wing wooden sport airplane is much better (with a span of around 130cm and weight about 2kg). Like the Calmato sport from Kyosho.

Regards!
Jan K
Sweden