Best combination for drag coils

I have been thinking about setting up a drag coil for the quad, and had it mind to use a 40x20 Ct AI coil, and probably either a Gp extreme or 3000 to run it, that way I can use battery power from the axillary battery on the quad through a regulator to run it and have the control box mounted back on the tow frame to reduce interference.

Anybody used a set up like this and what would you consider the best combination of detector and coil for the job?, I want to set it up as an independent unit that I can assemble on site, and want to be able to leave my 4500 that I also carry on the quad free to be able to just take it off and check any signals that the drag coil gives off.

I have been thinking that using a less sensitive early model detector and big coil will just give outright depth and ignore most small surface stuff, also running it from the spare battery through the regulator will enable me to run it as long as I want without battery changes, the spare battery I can also charge from the quads alternator output and it also has a small solar panel topping it up as well.

au-fever