Greg,
I have customers specify to me that they do not want their deck sprayed. Often, they tell me the last guy sprayed all over their house, outdoor furniture, etc, and made a mess.
I always ask what a customer wants, and carefully listen to them before I commit in my mind how I would do the job for pricing purposes. If I can pick up on one particular method they seem to favor for stain application, I use it to my advantage. When I tell them I brush everything, and they've had a bad experience with spraying, I get a huge advantage. Most people seem to pay extra for what they deem a premium service. So if it takes six hours, then it does, built into the price.
However, if I detect that the customer is ok with spraying, I'll consider going that way. Sure, it cuts down on labor time, but it also cuts down on the total revenue. I've always thought it better to make more $ on one job, then have to break down and go to another job site so frequently, as small faster jobs go.
Just some thoughts.
So what happens to the gallons of overspray that get on your tarps? How do you handle the soaked tarps without killing the customers grass? The oil based stains I use seem to really soak in, and make a huge mess.