Just an ubiased opinion, I thought the same way many of you guys did about it not being enough torque with fewer servos and had 3 8611s (not As) on my 39% ailerons and 2 on each elevator. The plane flew great so I never messed with it.

Then on my new yak, I went down to two aileron servos and can't tell the difference (Not quiet as large as the one you had in your example (mine are 6.5" to 4.75" taper)
I initially set it up with 2 on each elevator, but the plane came out tail heavy even with a pull pull on the rudder (pretty dense sheeting) and I was reluctant to pull 2 elevator servos (1 on each side), but to keep from putting 1.5#s of noseweight in the front, I decieded to give it a try. I knew I wouldn't loose the plane, I was just concerned if a regular 8611 would have enough tq to make it snap the same and not get blowback in any 3d. I was pleasantly suprised to find that I didn't lose any resolution or "needed torque" in the removal of the servos.

I'm in the same boat you guys are and just want what works the best in my plane. I fly unlimited and if I was losing any advantage in resolution or blowback, I would change it in a heartbeat, but it works fine.
I just keep reminding myself that we were flying 3d and precision with 2 - 3 8411s on their ailerons and 2 8411s on the elevators not that long ago with no problem. I think trying to use one 8411 on an elevator DD might be pushing it, but an 8611 has twice the tq and a 8611A has 2.5 times the tq.

Just thought I'd share actual real world feedback with you guys.

John