Welcome to the Forum.Read all of Rob Cooks books,as well as John Aldridge,Chet Falzerano,Mike Curotto(shameless plug)and Harry Cangany to name a few.
Most of the written info is in book form,and on sites like the VDF.Some of these guys,know more about vintage drums,then the guys that built them.
As far as expert status,that takes years of research and hands on experience.There's much information to be gleened,by just holding a 47 Slingerland Radio King in your hands,and knowing a phony,from the real deal.There's mountains of info out there,that I dare say,dwarfts E drums...no offence intended.
Just in American made drums,companies,models,sizes,year of manufacture,finish options,shell composition ,types of wood............It's quite a list.
So as long as you have a few years to spare,and accept that what you thought was correct yesterday,is no longer correct today,then vintage drums are great.For both their looks and sound.
Steve B