Summary

Original design was great, but I didn't need the extra height. This is a flat version and worked with any adhesive Magsafe disc with magnets.

I used this one:
https://www.ebay.com/itm/114931491426
I measured the eBay MagSafe circle at 56.54mm wide on my calipers

Final Offset version has a 60mm wide disc with 56.60mm cutout with additional offset to get the MagSafe farther away from my Tarmac SL7 mount.

Centered version has the same 56.60 cutout for the magnet and 60mm wide disc, Garmin mount is centered on the bottom