[DK on the road]

I have owned 2 of the official plastic holders. Each one broke while installing or removing incorrectly. Any motion away/outward from the glass will cause the plastic to break in the upper arch. Its good if used correctly and installed by the same person each time. Or maybe my monkey hands get in a hurry, not sure the root cause.

I now use a Home Depot 4" spring clamp with big plastic soft pads at the grip points. I would guess about 5 to 7 lbs of pressure with this holds it in place. I've maybe logged 20K miles so far like this without a problem. This is a 3" example, I'm sure mine is a 4"

https://www.homedepot.com/p/Husky-3-in-M.../207119474