Help with Antenna Mount

[JDaw]

The antenna hole for my 1969 C10 is in the cowl of my truck. Ive bought a few antennas that when mounted, are off to an angle. Theyre for fender mounts it looks like. Either way, they definitely dont fit.
My solution was to get one that could be adjusted, and it works, but its really ****ty quality. It has plastic pieces that I can tell will be an issue with time, and it fits a little loose.

Does anyone have another solution? I sort of wish I had filled the antenna spot and gone antenna-free when doing my resto but too late now.