Good morning.
I make some of my own handles. I have some for tools I bought without one and some I did not like the handle that came on it. :redface::redface: The trick, as I see it, is to make the handle that fits you and your method of using the tool. :smile-big::smile-big: There are all kinds of suggestions out there for the length and even some for the girth, but the bottom line is that you use it and it must be comfortable for you to use.
Some of mine have a very long handle as it gives me better control when using it. The best thing is to watch how you use the tool and then imagine it with a longer/shorter/smaller/larger girth. Then make the handle. I also add some larger dia. where my hand fits the tool as I have large hands.
The point is the tool should be comfortable for you to use.
I hope this helps.
Merry Christmas and Happy New Year to you.
Ron