you could always trace the perimeter of a P-bass, or purchase a template from one of several eBay sellers. dimensions won't get you an accurate P-bass outline since the contours are more complex than can be detailed with simple dimensions
it´s possible get a trace 1:1 scale or dimension plan?
best regards
NB
You're welcome.
When I made my first Les Paul shaped guitar some 25 years ago, I traced the shape from one that was hanging on the wall of a local music shop. Be polite and I'm sure they let You do the same where you live.
I'm not a Fender guy, quite the opposite really, so I can't help You with the drawing either.