I was in a Walmart looking for a gallon of white paint. Bright white, not an off white color. They were out of stock and I asked about using a light base? It’s very white but I was told I could not use it without tint being added. I ask

I live in a 100 year old house with stained shake cedar shingle siding. The roof rafter tails are exposed as is the roof material on the eave overhang. (3/4″ thick beaded fir like they used to put on porch roofs.) Five years ago I used to heat gun to