Well, it matters, because even going from 2.5 to 2.8 mm (actually 2.78 mm) made a huge difference.
The reason that I ask is if you used a 3/32 drill bit the shaft should make it through a stock port; a 7/64 (or larger) would not. And the drill bit would have to be undersize to fit in the port, so it is also possible that the hole is larger than stock if a 7/64 bit won't fit.
