Share 'Building the perfect professional chocolate kitchen'

Hi, I am planning to turn the basement of an old school house (from 1903) into a professional praline making kitchen, but need some advice regarding air conditioning etc. I know that high humidity is a big problem for the chocolate. Does anyone know the recommended percentage of air humidity in the kitchen (for ex "not more than 75%")? The climate where I live is very dry (and cold) during the wi…