I believe you're right in that the marketing is the key.
You have a highly specific target market for this kind of thing.
I like the design, but, unless you can churn them out by at least the 10s, you're not going to get anything like rich, I'm afraid.
I will (and have) paid in the price range of $75 to $100 for specifically and custom designed (as in, my basic design with the artist's interpretation and subject to my approval) for a number of sets of grips with the family "crest" patterned for a special family event celebration. The artist did a fine job, but I don't, for the life of me, know where she'll sell any more:
The artist incorporated the family design into the grip but the multiplication was done on CNC machinery.
Best wishes for an outlet for your talent.
w