I am preparing to tile over a 3/4" OSB T&G subfloor, using either 1/2" cement backerboard or a 1/2" thick layer of self leveling floor compound. The OSB floor is supported by wood I joists at 16"OC, engineered to L/480 specifications. The tile will be 12" & 18" Travertine marble. Would the cement board or self leveling compound be better for this situation? I would prefer the self leveling compound because there has been some edge swelling of the OSB, which will make a flat floor more difficult to achieve if using backerboard. If self leveling compound is OK for this application, what specific product would you recommend?