Length of board should be 3 full cross steps forward from mid starting turning point of where you land after a bottom turn...
Least thats how it was in the 60's...
My own thoughts
Im not a true believer that a board has to be super heavy to be a decent nose rider.
Alex Knost proves that the nose doesn't have to be super wide
The length matters but if you cant swing it into the pocket and all your turns are late, well you wont be noseriding anyway
Watch this video and then watch the end where the winners are standing with their boards..
a ton of variation with size and shapes..
Its all about the surfer in the end.