12' x 20' flat roof over exterior screened in sunroom. Newly installed TPO roofing membrane hot air welded and glued directly to the OSB sheathing. I plan on painting the exposed OSB ceiling of the sunroom. I need to know what is the best primer to be used. I was thinking acrylic latex primer or oil based primer. Which primer would be the best to use where the OSB ceiling will be exposed to the southeast Virginia weather conditions of a screened in sunroom?