Hi All...my project not done yet but almost (famous last words). Just about ready to tile up hearth. Does anyone know if using Custom Building Products ProLite thinset can handle the temperatures in this area of the hearth...see where I am pointing to in picture...its about a 2inch border where tile will overlap the gas fireplace. Custom Building Products told me on phone that ProLite is good for temperatures up to 190F. Your shared experience appreciated.