BTW, no matter what strength servo you wind up putting in the airplane, don't defeat it with your computer radio.
Hooking up your servo/connector/horn can blow a lot of the servo strength you paid good money for. A lot of newbies today think that the computer radio was made so they can snap the connections in any hole on the servo arm and any hole on the horn and they're good to go. Oh yeah, they might have to dink the TX settings to make the max throw 150% or such and change the center, but what the heck, dinking with the radio only takes a couple of minutes. And that saves them from having to take no extra time when they snapped the connectors into those holes....... duh...... wait a minute...... it don't take no extra time to put them snaping thangs..... duhhhh......
It takes not one second more time to rig your airplane one way or the other. So rig it first to give the servo mechanical advantage. Then check the throws for what the plans call for and go from there.
If you plug the connection into the inside hole on the servo arm, you're starting out with that servo having it's most effective output. It will draw the least battery (so you get more flights per charge, no big deal, but you do) and when you're flying the heck out of the airplane and all servos are sucking away, they suck less total amps (so you have less chance of starving the RX or *****g the battery pack's ability to provide amps). And the servo is going to have a chance to push it's max strength down that connecting rod.
Visualize this.......
You're moving an extension ladder. You're only as strong as you are. You're sorta like a servo that's rated at 40oz/in. You can give your rated output, but that's about it.
The ladder is collapsed. It ain't easy to move, but if you put all you got into it, you don't drop the sucker on the car that's parked in the driveway right beside you. (why didn't you move the car, you'd moved your truck didn't you
)
OK, you got it moved and extended. Now you're back down on the ground and gotta move it back where it was before you moved it and discovered it was in the right place the first time. So you are ticked, and decide to move it without collapsing it. OH JEEEZZZZ...... HONEY, YOUR CAR WAS PARKED IN THE ............ etc etc
The weight of the ladder didn't change but force needed to move it did. Your strength couldn't change to match. Same thing happens when you hook up your connections to the servo arm. Short reach on the arm (ladder collapsed) and your strength is sufficient. Long reach on the servo arm (ladder extended) and you now need two guys to move the ladder.... uh, the servo does what all electric motors do when loaded, they suck more amps and burn out or strip gears or stall and suck burn up everything that'll burn.
So when you are building that new magic airplane and it comes time to connect the rods to the servos, start out with them plugged into the holes closest to the servo. And go from there.
You basically wind up making the horn connection for the surface wherever needed to get the desired surface movement. That's outside the plane and easier to do anyway.