We use 1 Sprayer and 2 Wipers. You can use cold or hot water (hot Helps). We spray and wipe down the car at 60 seconds a car. We charge $2.00 per vehicle. We have no competitors. 60 cars in an hour @ $2 is $120 an hour (not to bad). We use all RO water. I have a soft water/RO sewt up in shop and fill 2 1000 gallon tanks in shop and use a farm implement pump to transfer to my 1000 gallon tank in my wash truck. Our entire RO setup was $7500 but RO water is a must in my opinion. 4 washes with hard water and you are then paying them to get hard water spots buffed out. We only wash car dealers on Thurs and Fri by deaker request. They want them ready for the weekend. We have 80% of the car lots in town which is 750 to 850 cars per week. Everyone does it different so I suppose there will be plenty of posts replying to this but it's how we work.