Not sure if this will help. When I did mounted shooting I used a product called Pistol Pro Grip that I put on my hands.
It worked very well but I’m not sure if it stays on the hands all day. It stayed on for the entire shoot, including holding reins, and handling things. Couple of hours any how.
Thats an interesting idea, thank you. Maybe just put a few drops on the finger tips before leaving the house...
Re “Pistol Pro Grip”, thank you!