Yes.
It turns out that you can precalculate a good starting position if you know the weight of the plane, the target speed, the line length and size. The idea is that the drag of the lines creates a catenary shape, and you want the leadout guides positioned relative to the model's CG so that the you do not excessively yaw the plane.
The link to the line rake calculator is:
http://nclra.org/Programs/index.phpI'd probably set the average of the guide(s) slightly behind this position, and then move it forward in small increments (1/8" -ish) and see if it helps or hurts you. There are certain corners that tell the most about guide position. They should be listed in the trimming tools.
Note that trimming is an iterative process. You get as close as you can on the initial things, like CG location relative to the wing MAC, then get the leadouts aligned to that CG location, etc. (Even the landing gear needs to be located relative to the CG). As you get the response rate you want (if you have to move the CG) then you should count on moving the line guides again, too. And so on. Early in the trim chart you are going to find that you need to get the tipweight adjusted correctly. I suppose my point is that there is an order to these adjustments that allows you to converge on a best answer. If you are way off in one regard, then tweaking the others to compensate will lead you astray....and that's the beauty of the trim guide--we are lucky to have had world champion competitors give us an optimized sequence and help us converge more quickly!
What model are you trimming? We might be able to give you some more specific info if we knew more about your setup.
Dave Hull
PS--If you are worrying about lines getting wrapped with a competitors in stunt then your circles are too close together, I think. I'll have to check with some of my flying buddies on that one....