Why would you spend extra money on flying a single with a wobbly prop and up/down wheels when you're going to be flying a twin that does the same thing? Don't let anyone try and 'amaze' you with the wonders of 'complex type'. It's not difficult and certainly doesn't warrant doing it before you do your multi-engine class. Read up on the theory beforehand, study the specifics of the Travelair before you climb into it and just crack on with it all at the same time.