This is an easy job, of course it is what I do. I wash up to 350 cars a day, and do it with 3 or 4 guys, but we are used to it. You will need 5 or 6 guys and will need to check the work.
Odds are that the cars that are coming in will be fairly clean. That will make it a ton easier. Here is how I am set up. I know it will curl the hair on the necks of some of you guys, but like I said we do 350 cars a day, without sweating it, averaging 50 cars an hour on an average day.
You will need to have the following equipment:
A pressure washer
A set of DI tanks
3 or 4 Chenille wash mits
A couple of 5 gallon buckets
a couple of NEW california water blades.
Some Microfiber towels, not a ton, just a few.
Some soap. For this I prefer Mequiars Gold Blend, or Zymol. They are both relatively inexpensive, and easy to get at a discount club.
The Method:
Have the trigger man rinse off three or four cars to get the dust off, if it is a regular fleet we will skip this step, because they really don't care other than the car is clean.
Have two guys with wash mits start washing the cars with the wash mits. You will want the soap to be two or three times heavier than recommended so that it will stay wet.
Have the trigger man go back and rinse the vehicles off, using DI water.
Have a GIRL (Has to be a girl, they are pickier about this kind of stuff) go through after the rinse, and using the California Water blade, squeegee the windows off.
You can walk around and rub shoulders with potential customers, and hand out business cards.
After they have been through the first section of cars, you can go through with a MF towel, and hit the spots that were missed. It happens, and this will help to improve the quality.
Remember this is a charity car wash, and that there is some room for error. If it was me, I would plan about 3 hours from start to finish.
With the DI water, the cars should dry spot free, and so you are just hitting the spots on the windows, and the few areas that did not get hit with a mit. You might want to rotate out the mit guys, because that is hard work, at this type of speed.