Chris a few options for you. Depending on how dirty your vehicle is, for a light dusting, I like using
Poorboy's Spray & Wipe. Basically use it in a similar fashion you would a quick detailer, except spray about 6 - 7 mists per area / panel, let it sit for 2 minutes or so, then gently wipe off with a
plush microfiber towel. The towels get saturated rather quickly when using that much product so plan on using about 4 - 8 per vehicle with this method.
For cleanings that are dirtier than a light dusting, I'd recommend
Optimum No-Rinse, which we do not carry at the moment. You still use a bucket of water, but do not need the hose. Follow the same procedures you would with a normal wash, however you do not need to rinse. A product similar to No-Rinse is QEW, which is often found on RV sites.
If you have any other questions or would like me to go into more detail with anything, let me know.
Ascension - Have you used the buffer in the past? I would not recommend learning to detail on a rotary buffer, there are far more risks involved with an inexperienced rotary user vs the potential benefits, especially if you only have 2 - 3 hours. The pad that is shown looks to be a cutting pad, which you'd want to apply a compound or medium cutting polish with. I think it is far too aggressive of a pad for that machine. When I start off with my rotary, I start with a soft foam finishing pad from Lake Country and work my way up if I need more bite. It only takes a second at the wrong speed, wrong angle, wrong part of the car to burn thru the clear coat or paint with a rotary. I'd recommend you pick up a hood from a local junk yard or practice on a vehicle you do not care much about prior to using it.
Could you list out the available pad options you have for your unit? If you do wish to still learn on that buffer, I can give you some product and pad recommendations for you to try.
You may want to still invest in a quality random orbital. Most detailers, even pro's, cannot finish down the paint properly without following up with a random orbital machine, otherwise you can be left with hologramming, buffer haze, etc. and your hard work is ruined.
Hope that helps clear some things up, from the looks of it, your buffer is fine and quite capable of doing what it is supposed to do, both power and functionality. I just wouldn't dive head first with it on your BMWs.
George
PS - After looking at your photo's I'd throw that pad away if it sat on the driveway face down like shown. Chances are you picked up some tiny abrasive particles that certainly will ruin your paint with a rotary buffer spinning at high speeds.