agreed. PPF is a bit different, but with a 36" unless you are planning on doing side panels, it will be more than enough to do bumpers and the hood trims/mirrors/etc that are typical PPF requirements.
99% of your biz will be front exposure. a 36" will do more than enough coverage to do the job.
best advice is to get a sample download from your vendor, and see what their templates are comprised of. i will bet (as i have looked into it extensively), most of them are for a 24" plotter.
if your vendor is unwilling to release a sample template, MOVE ON.