I believe it's a weight issue?
You guys using MINI servos (Hitec 225) on the elevator ?? why not 2 full size servos ?
The prepared cut outs are too small for standard servos the HS225 fit perfectly and have enough power so why make life difficult... Of course you could do what many do when they build an artf which is some or all of the following lol
1) Throw away the hardware on the grounds it is crap
2) Strip off the covering cos you dont like it
3) Fully sheet the whole plane cos you are going to overpower it
4) Make it so heavy by over powering it that it needs better landing gear which of course makes it heavier still which means you need more power.
5) Spend loads on top quality servos that are not needed
6) Make sure that all your servos are digital so you need a bigger battery and hence the weight goes up again
After doing all this you could just decided that you have bought an ARTF and trust it and use sensible equipment and the correct power for the plane..................... Still each to their own