[LMP]

I think you’d be better off factoring IN the board size, then using a (scalextric) track designer to design a layout on that board, and then route it.

Agree with Steve above, a figure eight will give you nothing except construction hassle. You don’t even need two lanes if it’s purely for testing. The tracks your proxy cars will race on will have a mix of curves so you should try and include a mix too. You should at the least have a fast corner, a slow corner, and an s-bend with change of direction.

I used ordinary DIY emulsion on the two small routed tracks that I’ve built. Run cars on it until it grips up and you’ll be fine. Both tracks were built for around £50 in materials.