You want to set up your mechanical linkage such that it allows as much physical servo travel as possible (i.e. short servo arm and long throttle arm.) That will give you more servo resolution to play with resulting in less throttle movement per amount of stick movement. This will make the throttle less sensitive. Also, center the servo arm so that when you are about 1/2 throttle the servo arm is centered (i.e. 1500us) (This may be your problem)? This will make you overall travel more linear. This is also where a servo programmer comes in real handy!

Then, you limit your servo travel via the transmitter to prevent bottoming the servo against the throttle stops on both ends. When you get the mechanical settings correct and transmitter programmed correctly, then you should have your trim adjusted slightly below or at center. Then you can use the trim slider switch to actually lower the throttle to change your idle, right on down to shutting the engine off. Of course you have to remove the throttle stop screw to do that. While you are at it, you may want to remove the throttle spring too. That way the servo will use less power to hold the throttle open.

Once I get things set up like this, before I start the engine, I bump up the idle a few clicks and when I get ready to land, I bump the idle down a few clicks. That way, when you are on a hard surface runway, you can slow her down enough to actually have it sit on the pavement w/o moving, without flying around with that low of an idle. Gives you an adjustable high and low idle, on the fly, so to speak.<o></o>