Other than the ones the other guys have suggested, you may have to go to a hang on to get any larger platform. Even my 14's take up most of the platform on mine so I can't imagine 2 sizes more. I have one hang on that is several years old made by API that has a great platform size and large seat....but it's not a climber. If you just can't get one that suits go to a hang on and get some climbing sticks? Good Luck