Filling out the papers now!!

. (Only partially kidding).
I am not really a bat collector, but can someone educate me on how to feel good about these negro league bats? I understand the concept of side writing on a bat, but is that it? Does PSA / DNA actually have records that tie the weights and lengths to certain players, etc? New to this, but some one of a kind things coming that is for sure!!!
WOW!