When I was building the wings I take a 5/8" tube that is sharpened and bore a hole of the servo wires because I am using to servos for my ailerons, one in each wing instead of the one single one shown on the plans. I put my servo at the center of each aileron. It was all done after I sheeted the cores and they were dry. I lay out every thing on the wing, cut the sheeting for the servo hatch, I am laying the servo on its side and it is fastened to the bottom side of the hatch cover. It is totally in the wing. Only the rod comes out of the wing.

Next I layout and cut for the landing gear retracts , cut the balsa, cut the foam out,I use my solder gun with a piece of 14ga copper wire installed in the place of the normal tip, and box it all in with 1/16" balsa. I used a couple of pieces of 1/4" x 3/4" maple for the landing gear to mount to with 4/40 bolts and blind nuts.

You can bend the copper wire in the solder gun to be flat about 2" wide to scoop the foam out of the cuts.

I put a 1/4" small tube in for the air lines to slip into later. To make these I just use the clear plastic tube the I had left over, they came from a piano wire package. I heat it with my monokote heat gun, twisting it in my fingers to heat it evenly, when it is hot enough it will bend, rotate it so it doesn't kink, remove the heat and it is hard in a second. Now I have a nice tube with a 90 degree bend in it. I used this to go to the center top of the wing from th retract compartment.