Well MIS usually means a shorter incision, and quad sparing is a technique to not effect the strength of the quad muscle, so they are two different things.
I would caution against using a surgeon for any big surgery who has not done at least 100 of the procedure you are getting. There are studies that the most mistakes are made in the first 100 procedures new to the OS.
As far as eyeballing, I believe it is more by feel that the surgeon can tell proper alignment, etc. Although now they use computers for alignment, I told my TKR doc computers are fine, but I expect him to know by feel if everything is OK. He shook his head yes. Luckily for me he has done 4,000 of these, so I don't need to worry, and I also know quite a few past patients of his that came out excellent.
It is a challenge to get the prosthesis into very small incisions, if the incisions are ridiculously short, I'd be careful about that OS.
Hollie