Cutting in Rear Quarter Panel Vents

[gmg0005]

Currently in the body work stages of a 68' Camaro and have been trying to track down a little more info/insite/opinions of possibly someone that can speak from experience on this topic. Any help would be greatly appreciated.

Does anyone have pictures on cutting functional rear quarter vents on a 1st gen camaro? I am currently trying to decide whether or not I'll be doing this on my '68 but I would also like to keep the rear windows functional so they can be rolled down. Does anyone have rear quarter glass in their car they could get a few measurement or pictures of the amount of room between the window track and body in this area?

I have searched all over the internet and have came up with a few pictures but no details. Too big of a decision to make and not make the right choice. Below is an example I found of a nice car out a shop near Boston I believe. I would like to make mine functional if I'm going to go through all the bodywork to make it happen.

Thanks for the help