I have a 500/1 Beatle bass and a 502 Club and there is absolutely no space for a strap between the top of the body and the underside of the fingerboard/neck. Maybe Paul's '63 and the earlier one had a big gap there. Go to the Hofner community web site and ask the Hofnerhounds forum: http://www.hofners.co.uk
They may have an answer. I never wanted the Hofner strap on my basses because of that steel dog latch attaching to the tailpiece. I thought that it would scratch the body.