That's some clean looking work there...
Hey just to chime in about the deeper theads. Another way to deal with that, is to use a very small amount of medium strength thread lock...
The final position of the focus adapter in relation to the front of the host, is determined by the lens position at focus. This gap can be adjusted by the module position inside the heatsink for most builds with an AixiZ module.
With some builds, like the Kryton, you do not have an AixiZ module to adjust the position.
So another way that would be very easy, is to thread the focus adapter deeper. That way when you thread it onto your lens, you can adjust the position of it, by how far you thread it onto your lens.
The only thing you will need to do, is use a very small amount of medium strength thread lock to set it's position on the lens.
The easiest way, is to have your lens installed into the laser with some Teflon tape on the threads so that it is 'snug'. And at normal focus.
Then, put a very small amount of medium strength thread lock onto the lens threads, and put the focus adapter onto the lens. Leaving just a minimal gap between the face of the host, and the back of the focus adapter. (a small gap is recommended in case you want to focus it in for a farther distance)
Then let it sit for 20 minutes or so, for the thread lock to cure.