Quick message about this before i leave town again for work and won't have a computer.
My theory on how this works is with the use of something like this.
https://www.mill-max.com/new_products/detail/2Now obviously these need to be large enough to fit the switch pins but also small enough to fit the PCB holes, now these specific mill-max through hole sockets have a lip on this which i think is a good idea but leaves less room for tolerances as i think the fatter lip part should fit INTO the PCB holes to make the switch side of the PCB perfectly flush rather than having the lip sit above it, by having this lip here it'll hopefully leave a little crevice where solder can help make the connection between the PCB and socket.
Now this will also have to be plate mounted so that the switches will "lock" in place which makes it removable as well so the plate can't be thicker than 1.5mm or will have to have the lock points milled out like GON plates.
Unfortunately i don't have time to explain more but hopefully this is enough information for someone to work with and test since there's many people here smarter than i.