I know you have searched this out pretty well so let me add soomething to your thinking. My concern with the Rhino lining is that the surface is impossible to get completely clean of rust and moisture and that the lining will trap it underneath and create the same problem again.
Over the years I have tried many things but had the best results with just cleaning and rust removing the best I could and then spraying the surface with a mix of oil and diesel fuel. Then i use a leak-proof battery such as an Optima and I have never had a problem. I also use copper battery cable ends.
My current mess, as noted earlier in this thread, was a JD 790 that I bought with only a hundred hours on it and a severly rusted out battery area with a leaky battery. That's my two cents.