johnno
I went with the small sprayer JD sells with the "lawn & garden" tractors. It holds 25 gallons and is electric (12 volt).
Mounted it on top of the box scraper. To get power, I installed a start solenoid on rear side of roll bar with a lighted rocker switch on top of tool box lid. Plug from RV place fits in hole in hyd. attach bar at rear of tractor. Add a couple of inline fuses and its done.
I have it on the back of my 4310 and just finished spraying 10 acres as well as a bunch of berries etc along high bank with the wand. It works great.