Dear Charles,
I completely understand you. I used to say: "the handle is a kind of an underwear" -being so close to the person.
I always learned all my colleagues did not take a rest, until the handle is not absolutely fit into the hand, and holding style.
Naturally, it is not equal, how he holds it. Either grabs with full fist, like hoe handle, or just "hanging" the handle on four fingers. (I prefer this, with the thumb on small stand, or in a groove.
The absolute solution made by a late friend, a dental technician: he simply grab into a piece of Dentacryl*...
*Everybody should be familiar with this or similar material in pink: this is the basement of dental prothesis