[Graham]

Fly Porsche RSR is 58mm at the rear.  Fly Porsche 935 is 62mm if the body is raised as the fender tappers down towards the edge.  Possibly 2 different classes?

As you know it is always difficult to generate a "slot car list" which is not biased towards certain models" and I had intended that the Class C & D cars would naturally split up into narrow Monte Carlo Sports Cars and wider TDF Touring like cars. But on reflection I don't think that worked well.
However today I also realised that the Porsche 934 could not enter the TDF Category D Category as the competition ended in 1974, so it is not listed as having been entered.
I believe the solution is to bring forward the Class F Monte Carlo Modern Rally cars to 1975 and narrow the time frame for Category C to 72.
 So effectively the Camaro 69 remains in Category D, and the Porsche 934 is now in Category F.

The idea is to enable the widest range of cars across the entire period, and place the Slot cars into Categories which have some historical reality, but also equally important to have the best "Slot Car Competitive groupings" so we don't get too many of the same or dominant models.
Not an easy task......