FWIW, I'm not sure that I agree with the observation that secretarial Fernando autographs exhibit the long tail below the signature.
When I lived in So Cal I managed to get Fernando's autograph 3 times in the wild.
For your consideration, please see the attached photo of the autograph that he signed for me at the LA Open at Riviera CC in Pacific Palisades, CA in the early-mid 1990's.
OT, so sad about the fires in LA. RIP to the 16 people that died in the fires.
I spotted Fernando and his son walking in to watch the tournament and managed to get this autograph on my golf periscope.
To say that he was a reluctant signer is the understatement of the year, but I did get it as the result of some serious begging from my close friend when I initially got rebuffed.
Note the long tales
I wouldn't necessarily subscribe to the theory that secretarial Fernando autographs were the only ones that had this characteristic.
RIP Fernando, one of the great characters in the MLB.