So far I have chatted with just one neorotologist, have more meetings next week.
The one I spoke to said if we do surgery, it should be retrosigmoid for my case.
He mentioned the "hole" size they would make is generally between the size of a quarter to a half dollar.
5cm = 2 inches = about half dollar or larger.
Maybe most surgeons now do retrosigmoid with a hole about this size.
I believe the guy at Skull Base Institute is doing something different - totally endoscopic, meaning he cannot actually directly see the area he is working with his eyes, he is using cameras and a computer screen. That's what others are saying is a concern, he can't really see if the surgery causes a small bleed to happen, which can be big trouble later.
Probably Hopkins is doing regular retro microsurgery, and just emphasizing that the entry hole is small ish. I am sure you can call and ask them.