69"... Don't' really know my exact waist as it depends on who is measuring. Based off my last PT test, 32" waist. I had to use spacers to bring the seat up, you likely would not need to do that. I also had the regular version. My dad had the wider version and they did not hold me well.
Personally, I'd buy new unless the used one is mint.
Personally, I'd buy new unless the used one is mint.