Should be Shure/Ety size, which I think is 2 mm (unfortunately don't have that tool whose name I don't know to measure the exact diameter).What is the nozzle size of the mini2?
Can I fit a larger tip bore with some modifications?
Careful shrink tube application would be a possibility, but removing it would have to be done with even more care. You could also remove the foam parts of a foam tip of that size and use it to widen the diameter for larger bore tips.
But as mentioned in my review, excessive tip-swaying is probably not the best idea due to the flexible nozzle.
/Edit: Fixed some stupid autocorrect errors.