All I did was add a bit more length to it so it will fit an optic. Probably added too much but at least that allows for more compatibility. And my CAD is definitely not perfect. I used 4 of the linked magnets, 2 wide 2 tall and it holds it quite well. You can screw it in or just VHB it.

From the original model: 
This is a magnetic pistol holder. Can be mounted to the dash of a vehicle, the side wall of your gun safe, under a desk, under a night stand, inside a center console, etc. The possibilities are endless I needed a place to put my pistol while driving, so that it's not hard to get to due to my seat belt being buckled. I found that this is also a handy way to store my pistols in my gun cabinet as well.

It fits for my Ruger SR40c and my Ruger LCP II, but I gave one to my neighbor and it fits his Glocks as well.

Make sure to get high quality magnets that are very strong, or your pistol will just fall out.

These magnets fit pretty good: https://www.amazon.com/gp/product/B07QWMHGHZ/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1