Single story, modified L-Plan house, built in 1893 with 12' ceilings. Location: East Texas. Should I insulate the walls and if so, with fiberglass bats, blown-in material or what? Exterior is original cypress lap-layed planks. Studs are true 2X4. Interior wall surfaces are 1X8 horizontal pine planks, not tongue and groove. I intend to remove all baseboards/trim, etc. and add 1/2" sheetrock, then replace all trim. I've been given about every different kind of advice on this that you can think of.