I am building a 1"x24"x36" sign out of maple. It is going to be an outdoor hanging sign (in upstate NY) that is engraved on both sides. I realize maple is not a great choice for exterior, but that's what the customer wanted. It will have a sort of "roof" structure in an attempt to protect from some of the snow and rain precipitation. Temperatures are often in single digits or colder for many weeks in the winter also. What would be a few of the options for clear finishes in that extreme north country weather. Any and all help is appreciated. Thank you