These'll go on the face to be DPAD and ABXY. The switches are lovely and i got them at a good price (YMMV but the seller DIYhz on amzn has a selection that appeals: https://www.amazon.com/gp/product/B07FS55G9P/) but they're not what you'd think of as gamepad buttons. This project has to be usable, if it's not usable i've failed, but i'm prioritizing aesthetics ahead of Gaming Excellence.

The buttons are 6mm across and the outside of the threading is something like 0.26". Maybe there's an established, proper way to seat these but experimentation brought me to marking the blocks, gouging a little divot for the drill bit tip, then cutting a hole with a 1/4" bit and finally cutting threads with a 7mm tapping bit. Cutting a bigger hole works as does strong-arming the switch's threads into the plastic but those techniques are less precise.

Squnching the nuts down is still a bit of a pain.