Mine is mounted to a SW Motech plate that replaces the pillion seat. I use a BAM Sandstorm tank then I drilled holes in the plate, used four spacers and bolted the tank holding brackets they include with the tank to the plate.
A quick disconnect and a turn of the key and the tank is off.
A small tank, plate and needed hardware, hosing, clamps, etc can be had for under $400.
I have over 15k miles on first a 2 gallon and now a 5 gallon tank with this setup without any issues with the mounting.
I originally used the vent to pull fuel, but am now moving to a drilled tank bulkhead with either gravity or a small pump due to a fuel pump favor.