One thing I tried with my Rhino and boom sprayer was a front mounted guide. I took a piece of 1/2" steel rod and hooked it to the brush guard so it extended to the edge of my spray pattern and then twiseted an orange marker flag around the end so it almost touched the ground. That worked well for doing the driveway. I was spraying the field as happy as a hog in deep mud until I realized I was double spraying everything. I only had the guide out the left, driverside, so when I made my next lap around the feild I put the maker on the tire track from the last round. I forgot about the right hand boom. So by putting my marker on the tire track I was double spraying everything. It took about two rounds to figure out what I was doing. Then I put the marker what I hoped was 1/2 the distance beteween the old trakcs and my new path. Worked pretty well.
I also thought about doubling the lenghth of my marker so I could just leave it in the old tracks but it would have been too "bouncy". I didn't want to take the time to build a, for lack of better term, "truss" to support the end. I was gonna put a three foot or so piece of steel straingt up from the Rhino end of the marker and weld another 1/2" round to the far end to make a triagle. That may have cured the bounce but I think it would have swayed too much.
Anyway, it helped me. Hope this is clear enough to understand.
The 'Bonker