Zippi,

What voltage and mAh is your on-board battery that you are running your Hitech servos off of?

Having only built and flown .46 up to now I never really thought about it, but it looks like the extra 1.2 volt cell can really make a difference in torque (power) and while drawing all that power, you need more of it so it's a good idea to increase the mAh size?

Looks like I might be on the right track with servo selection after all.

Your Hitech HS-635 (high torque) looks similar to the Futaba S3010
http://www2.towerhobbies.com/cgi-bin...&I=LXFRS6&P=ML

While the HS-645 (metal gear, high torque) looks similar to the Futaba S3305
http://www2.towerhobbies.com/cgi-bin...&I=LXUZ89&P=ML

I'm thinking a possible servo setup might be (if sticking with all Futaba radio gear) :
1 - S3305 - Rudder
2 - S3010 - Elevator
2 - S3010 - Ailerons
1 - S3004 - Throttle (a standard ball bearing servo)