I find GC car shampoo to be a very high-quality product. It's available locally, has excellent lubricity, long-lasting suds, and is a great value if purchased in the larger sizes. I went ahead and bought the large 1.25 jug from Costco (which should last me a good long time). I transfer the liquid to a 4 oz. flip-top bottle that I have marked 1 oz, 2 oz, 3oz --> greatly helps when I am dispensing so I don't pour too much or too little. BTW, I bought the 4 oz. bottle in the travel section of my local Wally-world.
Take care everyone,
MCA