I'd pick Max here. Morrison is bigger and more powerful, but Schmeling was excellent defensive fighter. He didn't have problems with left hooks, which was Morrison main weapon. He'd make Morrison miss in first half of the fight with adding some powerful counter rights. Then Morrison would get tired and got stopped late or decisioned. Of course early KO from Morrison is not out of question, but I don't think it's most likely scenario. Max could struggle against taller and rangier fighters, but Morrison is only one inch taller and he has the same reach. Max made far better boxers missing and he himself could find chins of better defensive fighters than Morrison (Louis and Sharkey being the best examples).