Your assumption on the vertical location is basically correct. I like to have the bell crank near the vertical and fore/aft CG location to avoid side or vertical loads on the leadout guides that the lines can impose. This could cause wear, binding, or in the worst case the guide breaking loose. I'm not sure of the current, accepted, precise definition of line rake. Generally related to how far back the leadout guide is relative to the bell crank.
Chuck