Well, I had to try out my newly-installed electrical socket in my parking bay, so I got out my power washer and mixed up a fairly concentrated snow foam (Ultimate Finish's in-house stuff, they sent me a five-litre container of it, and due to having to faff about with extension leads in the past to use the power washer, it would have been a lifetime's supply).
I thought that I would try snow-foaming the car before I rinsed it. I can't give a scientific analysis of the results, but the thicker foam "dwelt" well, and once rinsed away, I shampoo'd it with Gyeon Bathe+, rinsed and dried, then gave the upper surfaces a quick spritz with Gyeon QD, and the results are quite impressive. The car becomes very dusty very quickly at he moment, hence the QD straight after drying. The combination of Gyeon Bathe+ and Gyeon QD gives very satisfying beading whenever the car becomes wet.
No pics, sorry, because I didn't have my phone with me. Next time, perhaps.