I have a 250-000 QCTP on mine. The lathe has a locating ring around the toolpost mounting stud, and this is too big to fit the hole in the toolpost.
I suspect boring out the toolpost to fit would be problematic because it’s hardened – I don’t know whether anyone’s tried.
Alternatives are removing the locating feature, or doing as I did, and making a spacer. I used a piece of cast iron from a car brake disc.
I sometimes entertain thoughts of making some sort of indexing feature, hence the oversized edges, but lack of a roundtoit always intervenes.

By the way, the next size up toolpost might be better, but I already had this one, and a number of toolholders.