my concern with the boot style gun mounts is holding dust/gravel/etc that can scratch the surface.

Solid Hit.
I don't doubt that your system works. I just didn't want to buy a cart and modify/change/upgrade it.

If your area is like mine, I bet there are a bunch of carts with all kinds of extras already done to be had on craiglist or facebook market place.

Doing some work yourself though can save you some serious coin and quite a bit of the work isn't that difficult.

So my setup is a 5 x 10 trailer that was made for my EZGO gas. I bought it remanufactured (Franken-carted). Lifted, bigger tires, clutch kit, back seat, gun carriers, etc. Have around $4000 invested in all of it.

Next upgrade is likely to run me over $20k, so I'm really happy with our buggy. It sets in the shed and doesn't cost a dime.

My neighbor's hobby is doing all that. He'll buy a striped cart and make it into whatever you need. I originally wanted a gas cart but the electric works better with instant torque and enough power to do the job - and no noise or emissions.

I went with the Kolpin UTV mount that mounts inside the cab and holds the guns upright.