Speaker setup experts please?

Read through teh Wilson set up guide. If I remember correctly, it should answer many of your questions. For example, placement distance into the room is dictaed by how far you need to be away from the walls to avoid the first reflection.

Go here and see "avoid first reflections..." and
go here for excellent tips on coupling your speakers' response to your room.

Here is a very simple rule that works well for a good tonal balance (for me anyway).
Measure these three dimensions: distance from the side walls, distance from the wall behind speakers and the distance of the center point of the woofers to the floor. Call the dimensions a,b,c where A>B>C, A=biggest, C=smallest. Then set-up the speakers such that B^2 = A*C (B squared = A times C)