I use a boomless nozzle on my ATV sprayer. It puts out 5 gallons per acre at 5 mph and 30 lbs of pressure. It covers about 12' at that pressure. I'm SURE my track spacing is not super consistent, BUT... I typically get about 4 acres per tank load (25 gallon tank) and usually have a very good kill without a lot of missed spots. I put 1 gallon of Roundup in my 25 gallon tank and water. Spraying 4 acres to a fill up gives me a quart of active RU per acre. Probably overkill but has worked for me for years.

IF you have a way to monitor your speed and pressure, it's all math, mostly easy math. All of your spray tips will have a rate chart. X tip puts out Y gph at Z pressure and T speed. I use a single flood (boomless style) tip. I got wore out with booms with multiple spray tips. You have to run them at a consistent height to get your spray pattern correct (so as to overlap each ones spray correctly).

TeeJet (sprayer parts company) used to have a great breakdown of how to do this in their book. I'm sure it's online now. If you don't spray with something that has a speedometer, download a speed app on your phone or pick a gear and rpm on your tractor you're comfortable with. Mark off 300' and time how long it takes you to cross that distance in that gear and rpm. The TeeJet formula will let you figure it out.