Silicone is king!! he he!! The tiles are siliconed on top of each other, and the varicap is siliconed to the tile. The thin wood base is siliconed to the bottom tiles.
For the two copper straps that link the varicap to the coil on the side, the plumbing section in the local hardware store had these lovely copper clamps for use in anchoring pipes. They work well but you have to trim them a bit to fit.
Front views:
Rear view:
Side view: