I have to apologize for my imperfect research of first usage from term Gana. This may depend on that I don't take enough time for my research. I have had Solyom in my hands but don't see the pictured hilt at page 35.
What is very important to note: Huyser write on page 32 that Dr. Groneman in his studies about the keris observed that in the keraton of Jogya are keris hilts carried which are called Gana.
I quote: "Dr. Groneman vermeldt in zijn studie over de kris, dat in den Kraton van Djokja grepen worden getragen in mensch- of diergestalte, in den vorm van een djagoengkolf (d.i. mais). of van bloemen, die gana genoemd worden, of ook wel boomwortels zooals bij. op No. 25, die de menschelijke gestalte weergeven."
I am not very used to read netherlands but I try a free translation:
"Dr. Groneman described in his studies about the kris that in the Keraton of Jogya keris hilts are carried in human or animal design in the
form of maize cob or flowers (here I am unsure if it is the correct way of tranlation) which are called Gana, carved from tree roots, look at Pic. No. 25, which are showing a human figure."
This translation may have some imprecision but I am sure that the esthesia will be correct.
So the first usage of the term "Gana" in matters of keris hilts in written dokuments seems to go back to Dr. Groneman i.e. the years between 1910-1913.
So it seems that the "so called keris-lovers" thoroughly able to do a good research!
Regards,
Detlef