The only reason I'm rating Old Garp slightly below Kuzan is because of MF encounter on how BB wasn't ready for Akainu (who is slightly above Kuzan) while he didn't mind fighting Old legends
Per this battle , it seems like Old Garp ~ Kuzan or even Old Garp >= Kuzan
Silcbeard ~ fA Akainu =< Current Teach
Old Garp/ Old Sengoku =< Current Kuzan =< Admirals
Mihawk ~ Old Legends
Per this battle , it seems like Old Garp ~ Kuzan or even Old Garp >= Kuzan
Silcbeard ~ fA Akainu =< Current Teach
Old Garp/ Old Sengoku =< Current Kuzan =< Admirals
Mihawk ~ Old Legends