I might try one, my biggest issue is drying. The water here is hard, and the sun makes it difficult to dry the car before the sun does.
You may want to check out the products from Poorboys. They are known to work well in direct sun.
https://www.autogeek.net/poorboysworld.html
It's not the product, it's his water. I just taught an old friend how to correct paint on his '02 Audi in El Paso, and he had the same issue. So many minerals in the water and it was so hot even at 8PM that he had severe water spots almost instantly.
The solution we settled on was one final rinse after the whole car was washed, followed by a heavy application of spray wax/quick detailer and a drying with two towels. The spray wax helped keep the minerals from bonding to the paint and avoid streaking.
Correction was a burden - M105 flashed almost instantly and was dusting like crazy. Quick detailer on the pads and misting as we went helped but it was infuriating. M205 was even drying and dusting, which I have never experienced. We had to keep stopping to wash the pads of dead paint and dried product since he only had two.
Now that it's done he's decided that it will stay in his garage - smart decision with the desert weather, and I've sold him on the magic of waterless wash!
https://www.griotsgarage.com/category/education+boss+foaming+system.do
This was using 1oz of Meguiar's Hyper-wash. I use it more of a washing aid rather than a pre-soak. Load up the panel while I'm washing and it helps with the lubricity. You can't do this in the sun though, as it will start drying real quick.
