I'm planning to purchase a Rad Rover step through this spring. I expect I'll add a rear rack but was also curious about maybe a SR Suntour SP12 NCX Seatpost. My problem is that according to the specs they are for riders between 140 and 180 and that's rather a narrow range and one that I at 200 don't fall into. Are there other choices out there that will fit this bike? Thanks.