The one I pulled out of a 150 to take the measurements was snug. No slack. I wouldn't call it a press fit (you don't have to force it, or drive it in), but you do have to push it a little into the hole. A pretty tight fit. This is what I got back from LMI.
Thanks for writing. That 10mm measurement is accurate. We sell a headstock drilling jig, which accommodates a 10mm brad drill bit to bore out the holes for the tuner bushings and machine heads. I hope this information is helpful, let us know if you have any other questions.
Best Regards,
Kyle @ Luthiers Mercantile
I could come up with a way to take out .1mm+ without resorting to a headstock drilling jig, but I was going to put these tuners on a 555. Not going to do it on that one. The safe way is to do what you did and replace with Grovers, or find another tuner that has a 9.9mm hub.