Hi Michel, we have had several discussions about these tyres in the past and you will find various answers to your questions. The billboards are a beautiful looking tyre and would definitely be the pick for the vintage look. No, they are not DOT, they do tend to wander somewhat on uneven roads, they tend to flatspot when left in the garage for a prolonged period (sorts itself out after a couple of miles), depending on how you want the car to feel or look and depending on how much you can tolerate the tracking really depends on what choice you ultimately make. The Billboards grip in the dry and have really good grip in the wet (my experience), put them on, try them out and you decide whether they are for you or not.
I LOVE them!
Stef