I agree that the modern touring cars are running lap times so close to 1/8th cars that separate practice sessions are not needed based on that difference. It would make more sense to control practice based on 'skill' regardless of the class of car, but that's nearly impossible to do.
The GT cars will be slower, and beginner-prone, and therefore might benefit quite a bit from a separate practice time.
However, keep in mind that at least those cars are big, so they are relatively easy to spot in one's peripheral vision going slow down the back straight, so high-speed collisions are not too difficult to avoid.
Does anyone else care to weigh in on the idea of running the GT cars 'backwards' on the track compared to the rest of the cars? I think it would add another level of fun to that class, especially for the regular TC and 1/8th drivers who might get a kick out of trying out their favorite tracks in the opposite direction as well as with a totally different type of car.
Of course, this would fit in well with the idea of running practice for the GT cars separate from the rest of the cars. I'm thinking that just 10 minutes out of every hour of practice dedicated to the GT cars would be enough, unless the attendance of that class warrants more time.
But whatever Ron decides on I'm fine with.