Follow up post… I got offers to help and took up two of them. I have to say, I’m glad I went on with this, I’ve just built my first driver with one of them and it’s a massive time saver! So thanks for the help with this, it’s one of my ideas that actually worked out very well, at least with the help of two people who know what they are doing when it comes to 3D printers. The surface might not appear to be smooth in the photos, and I did receive some sanding paper with one of the packages, but they are smooth enough by far for applying solder paste with stencils so there is no need for sanding.
I did need to file out the outer hole on both of them because they where made with only my measurements but it was just a minute of work. Ultimately that was a good thing because now the drivers are press fitted with just a little force, once in they don’t move around at all and they are easy to remove. So better a little too mall than a little too big. Some photos:
The first one I received was the yellow one, driver fits snugly in place by pressing in.

The depth of the shelf is perfect, and the surface is perfectly smooth for this usage.

Applying solder paste with stencils was a breeze, driver doesn’t move around and removal is easy:

However, applying solder paste on the first side has not been the issue, although easier now. The main issue was doing the back side, it was annoying and difficult. Now with these “PCB rest blocks” it’s as easy as the first side, the inner hole is wide enough and the block is thick enough to accommodate these huge inductors.

Here is the second one, it’s just as good as the first. Snug fit of driver, perfect shelf depth, smooth surface and easy to remove the driver without smudging the solder paste:


I really enjoy designing drivers and writing firmware for them, but not so much joy when it comes to actually building them. Before I’d mess up the solder paste a few times because I couldn’t keep the driver perfectly still when using those jigs from OSH Stencils, and doing the second side was even worse. Now it’s a lot smoother so I’m happy and grateful. Thanks guys! 