Cord wrapped handles provide a very good grippy surface.
I suggest that you have a hole at the end of the handle, to do the finish wrap in.
Take some wood, cut to shape and sand down the edges so they are rounded over.
Epoxy them to the handle slab, drill a hole through the wood, keep the height of the wood low, just enough to make a thicker handle.
I'd then glue some stingray skin on each side of the handle, and drill the hole in the end as well.
Then start your wrap, using wide shoe lace, works real well, see this other post for more info;
Cord Wrapping
also this is one that I did a while ago, now resides with a friend in Maryland!
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