My solution was to build box beam of balsa, spruce, and plywood contruciton.  It does tree tings,

1. Bellcrank mount,

2. Landing ger mount,

3. Splice the right & left wings.

All it takes is one simple slot to fit it in.  It weighs a couple ounces, but it's comparable to the many bits it replaces.  More important, I have confidence that it will work, which is the only thing that counts.

The second pitcher is a one-time fixture to cut the slots.

Note that Crist is "The Controline Guy", and his product IS foam wing cores. See the Vendor's Forums below. His method is the "industry standard" and has been done thataway for many years. Not that Paul's method won't work... Steve

As Bill says. Install a small ply plate both top and bottom of the wing also. The bellcrank pivot rod will go thru the plates and then get trimmed off. The plate will glue flat to the wing and fit between the fuse sides. My spar is plywood with .010 thk. clear G10 fiberglass sheet laminated on both sides for added strength. I also fiberglassed the center section top and bottom with 1/2 oz. cloth after sheeting.