None. If you have a favourite car, then try that and see how you get on.
I've never made a layout for a particular car. I just make a layout that I think is ok to drive - hopefully interesting. Down to person looking to see if they think it's something they'd like to try, and if so they can download - and delete if they don't think it's worth keeping.
The lane width for this layout is minimum 14.25 metres / 15 yards / 45 feet, so space for every car to be used, although some of the corners are bit tight for some. But a corner that might be hard for me to get round in some cars, is no problem to others who have ability to trail brake / heel and toe / use e-brake, have coordination, etc.
Personally, I'd find it hard to get round in FO8 and BF1, but that's just my level of skill. Or lack thereof.
When I put one of my layouts on my server, I start with UF1, then try every car thereafter (XFG, XRG, LX4, LX6, etc, etc, working through each car in the GARAGE screen up to the BF1). Eventually there's always someone who I can compare lap times to, especially XRT (for drifters) and BF1 (drivers who want to be top of leaderboard).