filler material for cork grip

So I have this old G Rod, I never liked the tiny foregrip. So I split a 4 in cork grip and glued to the blank
in front of the reel seat. There is a gap of 1/6 inch running the length of the grip. What would be best to
fill this in ? I am not concerned with looks, I just don't like the feel of the gap. Ideally it would be
something that sets up hard and sanded to make smooth,
Once this is filled in , I will probably wrap it with grip tape.

Any suggestions ?

thanks Mo

The filler I’ve used is found at Lowe’s or depot. Made by min wax I believe and comes in different shades. PM me if you don’t find it and I’ll see if I still have my partial tube to get a picture of it.