Maybe you could run the shaft through a belt loop.....LOL JK.
I will say that I have used a belt-mounted unit in the past and did not like it at all. It was far more annoying than I expected, and after 20 minutes I moved the electronics back to the shaft. Think about how annoying it is to have to take off your wired headphones every time you want to dig and multiply by 10.
I am 72 and new to this hobby. I bought the swingy thingy,Detector buddy, and the Minelab Pro 45. Once you get the Pro 45 adjusted to fit it is the best of the 3.It took me about a week to get it to fit right.It seems like a hassle to wear ,but your arm and shoulder will like it.I had to modify my AT Pro a little