Not sure there are many choices. The hole in the table is a MT2 taper. So I find a soft arbor taper that fits. I have that arbor. I have been using it to locate the fixture plate while I was machining the plate. The only other degree of freedom is how high it is. Too high, it gets in the way. So it has to be level with the table, which makes the arbor a pain to remove. I can bore a hole in the arbor to fit a pin. These pins could be turned in various diameters on top, with a constant bore in the arbor. An MT2 isn't very large, not quite sure I can fit a 1/2" hole in there and get a decent depth to diameter ratio. Might have to go with 3/8" or so.