Good question.... my experience with them is that they would err on the side of a restriction. That said I would build as high as possible and add in some overhead storage where possible...
i would go as high as possible or close to it as that would allow a lift to be installed at a later date and the possibility of codes changing to allow that extra loft or storage area. you can always install a drop celling over the areas that will have heat so your heating a smaller area and its easy to remove or change as needed