i just started riding maybe a month or so ago on a unicycle i got at my local flea market. the wheel measures about 20" in diameter, and i was wondering what the ratio was between height and wheel size for when i eventually upgrade.
It doesn’t really matter what you ride. You want to choose the wheel diameter that corisponds with riding style you are looking into getting into. I.e.-20’’ for trials, street, and freestyle or 24-29" (about) for MUNI or 29-36" for touring/road riding. It all depends on what you want to do. Since you’re 6’ a 24" wheel might be better than a 20" to learn on, but since you already have the 20" just stick with it.