If it were me, I would use 1/4 aircraft ply for the LG blocks. Carve away enough of the wing for a good snug fit. Mist the wood and foam with water, and apply a thin coat of polyurethane glue to both surfaces. Let sit for 15 minutes, mist again and press the LG block into the foam. Clamp tightly in place for a minimum of 4 hours at 70 degrees or higher. Polyglue likes warmth and moisture as it cures. Keep some Qtips handy and rags for cleaning up foaming glue as it cures (starting fluid soaked qtips and rags work great to clean up spills and foam). Or, you can let the glue foam up and slice it off with a razor after it has cured. Redrill your mounting holes, as they will have filled with glue. Screw in gear and go.

Hope this helps.

EDIT: I should add that poly glue will not stick to wax paper. I use that on the foot of the clamp whenever practical, to keep the clamp from sticking.