Building a fence sprayer?

What I'd like to do is use a 55 gallon drum of a three point setup to run an electric pump with a tractor and not have all the trips. Other than the pump, hose to a boom or spray wand, the nozzles, maybe a strainer- to keep junk out of the nozzles. What else do I need? Do I need to run a pressure gauge? Should I also use tip or nozzle strainers? How about ball valves to shut it off or just kill the switch? I want to put something together that works fairly well but I don't have much experience with spraying fields and such. I figured for all the more I'll use it it's not worth several hundreds for a commercial unit. Any ideas and hints would be appreciated.

i didn't use a pressure guage. the shurflo pumps are designed to run at a constant pressure and constant gpm rate. you just buy a particular pump with the pressure and flow rate that you need. mine's 45 psi and 2.8 gpm. i bought it on ebay for about $40.

i just use a kill switch to turn it off, a ball valve is just another complication.

what are you using for a herbicide? roundup? it kills existing vegetation but won't prevent new growth. i have some home made chairs i made from a tree trunk, i hunt from these chairs. i had the problem of weeds and tall grasses popping up around the chairs. mowing, weedeating, etc was just a hastle. roundup killed the weeds but they grew back. now i use pramitol. one application will last for 12 months. instead of spending the time and money making the sprayer, try using pramitol once a year. you still have to spray it by hand, but you only have to do it once a year.