Not really a new thread but got fed-up searching

[TheArf]

Well guys I have spent quite a bit of time searching but coming up with no definitive answer so here goes and don't get ratty.
I am looking for what the recommended off set is for the roadster wheels also the wheel width.
I am using Sierra hubs and I like the mini-lights so I intend talking to midlands wheels at the show this weekend.
I am looking at 15" wheels but don't know what the off-set should be, I think its like that electrickery, BLACK MAGIC

Arfon