Not My thing but if I were to do it I think a Dedicated 12V spot sprayer that didn't have to be cleaned after each use would be the way to go. I would also try and use a Pressure washer gun with a Flat Fan like a AIRLESS PAINT SPRAYER. I don't know, but I am guessing 2 to 3 gallon a thousand maybe more is needed to get Coverage.
From the Grass paint Jobs I have seen, I think Brown is Beautiful by comparison.
it is one thing to do a off label applications. It is total stupidity to post it on the world wide web and expect people to approve.
You can lead a Donkey to water but you can't make the Jackass Drink