There's no way to know exactly what the right size is for you without seeing you on a scooter and taking a measurement. Stand on your scooter with your knees sightly bent and measure from the bottom of the bars to the your waist and that's probably about the right height. Some people like their bars higher, some like them lower. It's all personal preference. As for flat riding, that's personal preference as well. Dakota Schuetz rides his bars really low and Tyler Bonner rides his bars really tall.