I start with glacial acetic acid because it is cheap. I mix it down to a 28% solution by adding 3 parts acid to 8 parts water. Then I add 1.5 oz of 28% acetic acid to a quart of water (or 45ml to a liter) for my working solution.(posted 8577 days ago)I no longer use an acid stop bath for most films. Instead, I rinse in tap water--four complete changes of water over a minute to a minute and a half. If I do decide for some reason to use an acid stop bath, I always give the film a water rinse first.
In regard to your question about the metabisulfite stop bath, the chemical, though essentially a salt, has a slightly acidic reaction, and so makes a good mild stop bath. It is probably less likely to cause pin holes in negative emulsions if you don't use a water rinse.