This is a permanaent adjustable mount I've designed for Valentine 1 Gen 2 radar detectors. It should work will for normal and highly sloped windshields.
To assemble this mount you will need additional items:A 5/16-18 tap to tap the holes for the set screw. You don't need to tap them all the way through the hole, just deep enough that you can tighten the lockpin assembly with the set screw.
5/16-18 x 1/2 " set screw.