You did not mention which country the catalog numbers were from, but since you included Brookman in the mix, I will surmise that you are talking about United States.
Aside from the perforation differences, there are different types of tagging that need to be identified as well. You will need to get an ultraviolet light to discern which tagging is on the stamp.
I have some photos and such, my question is where is the reference material I need to use to decipher what is what? Is it in the Scott catalog and I just am not seeing it? For example, I am not seeing "v's" or combinations like "av".
Is there a master type list of all variations of stamps? I haev also read, for example on the Frederick Douglass magenta and references to certain plate numbers. Where is the depository for this info?
I have been reading your posts BTW, holy knowledge Batman! It is appreciated that you share your knowledge so freely!