Does anyone use their computer radio's ATV (adjustable travel volume) feature at values greater than 100% to increase control surface throw. If so, how far can you go? Does it depend on the servo? I'm using hitec 605's and 645's.

try 150% ...it should work

For most radios the max end point of the ATV is factory set. Something like 120% or 150%.

Most servos have no trouble going to those values.

Yep I do ! It's a must for 3D flying in order to adjust your control surfaces to maximum throw when the linkage adjustment are maxed out (would always try to perfectly adjust linkages first).
You should have no problem with your Hitec's.

I agree with Texas 3D, use all the travel volume your radio can supply and adjust the linkage for the throw you want. This does two things 1) gives the servo the most mechanical advantage 2) delivers the greatest accuracy

I think the 9C goes to 140%. I have used this when I wanted to get the max throw but didn't have enough analog length. It is best to use this to get the maximum resolution of the servo and not so much as max throw.

It is best on Futaba radios to set the ATV to the max, and then use AFR to reduce it. This gives you the best resloution on the servo.

What is AFR? Never hard of that before!!

Thanks