I am still building mine & installed two servos in the rear just behind the last bulkhead. I glued in some 1/8 plywood that stretches from the top stringer to the bottom. I cut holes & installed servo's right below top stringer so it would not interfere with the pull pull cables for the rudder. In saying this I am sure I will need the weight in the rear as I am using a fox 3.2 in the nose. Hope this helps.

Gil