Here are my current thoughts on a servo layout. The rails are tack-glued in and can be tapped out if it doesn't look like this setup is the best.

For the rudder wires, I would have to cut two slots, about an inch long each, into the former. This should not affect its strength.

The receiver can fit on a tray mounted "on top" of the wing tube.

Does anyone have any comments about this proposed setup?

Thank you,
Richard