I'm currently using HS65HB in mine. If you're into full out 3D and wing ripping flying these are the one's to use.
Did have really cheap Tower pro 9g servos. They're ok for mild sport flying but you will strip the gears on full rates.
As for larger servos, the problem is not the weight, mine weigh 485g all up, recommended AUW is 20-25oz (567-709g)
I don't think the ply around the servo is large enough to be cut that much.

This is a really great little flyer and easy too, you'll love it.
Use HS65HB servos and the limit is only your flying skill

I'm using:
Thumper 3536 motor (1000kV)
50Amp ESC
11x4.7 slow fly prop
2200Mah 20C lipo
(No additional balancing weight)

Hovers at 1/3rd throttle and 8mins of 3D fun