Thought I should add my thoughts after picking up a new foam for easy washing.
With two kids under 2yo and a works injury leaving me with a bulging disc in my back, I'm not likely to be able to do much car washing for a while! I've tried a couple different snow foams, last being some left over ValetPro Advanced Neutral Snow Foam, always left with a feeling of it being a half decent pre-wash, but nothing more than that.
I highly rate the Bilt Hamber shampoo so with some positive reviews I bought 5l of the auto-foam.
I had a very dirty Mazda5 that has been caked in mud for a couple of weeks. Followed the dilution rate from the OP, and ended up with just over 50% of foam to water. Used about 300ml of the 1l with about 1.5 passes of the car.
Car was wet as it was beginning to rain heavily.
WOW
I had no real expectation of it working as well as it did, in fact it worked so well, I won't be getting my two buckets out for a mitt wash for a long while!
I then decided to by some Hydro2 Lite as I'd seen a lot of great reviews and again as above I needed something that didn't need much work.
Soooo easy to apply and wash off, took about 5 minutes for the Mazda5 and less for the Leaf. I can't vouch for the durability as it's only been on a couple of weeks, but so far it beads as good asl every wax/sealant I've ever used.
My future will consist of moderately dirty car getting a snow foam then anything heavier or monthly/bi-monthly will also include a wash with the Bilt Hamber shampoo, then every 3-6 months depending on beading a spray of Hydro2 Lite.
edit:
Just ordered some Garry Deans The Perfect Soap wash to try as I fancied something new and the feedback is amazing.