Hello, I am adding pesticide applications to our landscaping inc. I already have everything I need, I am now looking at equipment. Can a 4 gallon backpack sprayer do for example; a corner to corner application on a 1/2 acre lawn or will I be refilling + having to risk mixing on site? I am trying to decide if I can offer full services with a backpack sprayer to start out with. I don't plan on having massive amounts of customers for spraying immediately so no large routes. Thoughts?