I don't believe it is likely a good acid rinse as it is a weak acid and it has a strong flavor. Breweries tend to use strong acids, like hydrochloric, but these are a bit more difficult to handle. Obviously the flavor isn't a problem if you rinse well with water before using.
As for dilution, I don't see the point. Domestic distilled vinegar at full strength isn't going to harm stainless steel in any way. You are already getting so so performance at removing beer stone, so I would go full strength. Something like sani-clean while a bit more expensive is as safe to handle and would work at least as well.
If you are comfortable handling strong acids (gloves, eye protection, no kids around would be good ideas), get some Five Star Acid #5.