Perhaps this isn't such an easy answer!
I'm 35 and got into pre war collecting about a year ago after a lifetime of modern (or what *was* modern when I was a kid)
I'm building a Phillies T 206 set and am at 8 now in sgc 40 slabs.
My question is: Is there a specific pattern in back variations? Are there only specific cards that have the serious SP backs? Do all fronts have all backs? For instance, does someone like Otto Knabe have Piedmont, Polar Bear, Hindu, Sweet Corporal....ect? Or are there specific back checklists only for specific players? Also, are there, generally speaking of course, ratios of known cards across the board per back variation?
Thanks for any help. I think this thread could be a huge help to many and perhaps I asked too much! I do have a few variations and would like to complete my Phillies set, in time, with all the possible backs (within reasonable cost parameters )