This is my go to for a car wash place as I control how much contact washing is done. Automatic washes scratch your clear coat, Japanese cars have soft clear coats so that doesn't help either. Touchless are better but very high pressure can also grind dirt into the clear. Prior to paint correction I'd use the pressure gun w soap, brush, and spot free rinse. Just those three. Daily driver scratched up truck. No longer scratched, now compound and polished with a Griots 3-1 Ceramic spray wax applied. My truck is vastly improved so I'm much more careful.
If you have very nice paint or a new car I'd recommend you carry a bottle of ONR, McKees 914 or P&S Absolute rinseless wash pre diluted to 1:128 or 1:256 to pre treat the vehicle or at least the lower panels before paying the car wash and starting the count down. Make sure to shake the bottle a bit. Pre treat the wheels and tires ahead of time with a wheel and tire cleaner. Numerous at auto parts stores. Let the ONR (Rinseless) sit a few min. Use some wheel brushes if you have them or the foaming brush they have at this wash to quickly work on the wheels. Don't want the wheel cleaner to dry. Then high pressure wash off the wheels. Soap and wash how you see fit at this point. If you use the brush on the hose make sure there are no sticks or sharp objects in it that would scratch up your paint. The bristles themselves will leave some swirl marks. Nature of the beast.
I'd personally fill up my own bucket with my own soap so I can control the PH levels. Hand wash out of that bucket. Use the pressure gun to rinse out the wash mitt frequently then dunk back in the soap bucket. Car wash wash places use high PH soap which cleans very well but is hard on coatings, waxes, and Sealants. If you have no active paint protection use their soap forget the bucket. You have no coating to protect. Just Raw clear coat.
If you have no wax or ceramic coating I'd get a spray bottle and apply a spay on when wet protection after rinsing the soap, like McKees Hyrdo Blue (worth buying a bottle) that activates with water. You will then have really good water beading for a couple months. So rinse off soap, spray McKees or your choice of spray on when wet protection then rinse that off. This is a rinse aid. Towel dry with good micro fiber towels unless you have a blower handy. Griots, The Rag company, luxury microfiber, Gyeon, Chemical guys and others all make high GSM 1100 plus dedicated drying towels. "The Liquidator" on Amazon is nice. Only use them for drying. Don't let them touch the ground or dirty lower parts of the vehicle under bumpers etc if they are dirty. Use a cheap towel like Costco yellow ones down on those areas.
Basically I'm at the point of only using this car wash for the high pressure spot free water. Good on wheels and lower panels etc. This place would be perfect if it had a standard pressure washer gun hose hook-up (3/8" quick release) w de-ionized water. That way you bring your own foam cannon and do a very high end two bucket wash. Slower so they would likely make more money on people doing a hand bucket wash. Plus they would supply no chemicals.
Water spot tip if washing at home in sun or on the road. If you buy (1 gallon) Formula Four spray wax (made for automatic car washes) Dilute it 1:10 or 1:20 in a spray bottle, spray on after rinsing off soap while car is still wet and it will kill any hard water and leave a bit of short term wax protection. Don't let it dry. McKee's 37 Hydro Blue would be even better used the same way but one panel at a time. Spray hood rinse. Spray fender rinse etc etc.
There are many other products but Superior brand formula 4 is very economical. See Wilson Auto Detail on you tube for the formula 4 tip. McKees is better longer term protection. Both on Amazon.
Just saw the No bucket sign. Guess that won't work read more