[KWScott]

The 3D Hammer Downs used in the 2038 World Championship was built to 2.5 x Car Wars scale... I went through all the arguments you're having now way back then... Here's why I chose the scale I did.

Car Wars is 1:180 scale... 1 inch is 15 feet. (Close to N Scale)
2 x Car Wars is 1:90... Close to HO Scale, but models are generally too big for a 1x2 inch counter in this scale.
3 x Car Wars is 1:60... which is right in the ballpark for the 1:64 Hot Wheels, but again, I found the cars to be too big for the counters in many cases.
2.5 x Car Wars is 1:72... which is a Very Common modeling scale, and there are many, many planes, trains, and automobiles out there that fit... But what I found is that 1:72nd models are too big for a counter, unless you're dealing with small cars. However, the Model Railroad industry has Myriad choices of (easily paintable and modifiable plastic) model cars at 1:87 HO Scale, which while at 1:90 were too big for the counters, at 1:72 work just perfect...

Oh... Yes... Important point... I mounted all the cars on appropriately sized counter bases (1.25 x 2.5 inches), so the turn-key and measurements, and arcs were measured off the Counter, not the Model, which makes everything play just like the 1x scale game.

At 1:72, Hammer Downs is about (I'm slipping into memory here... I can update later with real dimensions later once I get home) 7ish feet across, which made a long, but possible reach to the middle of the arena. At 3x scale, it would have been Way too big.