I've been riding unicycles for about 30 years or so and let me tell you, riding a 6 foot giraffe unicycle is no easy task.
I tried a 6 footer once and it was pretty scary to say the least.
There is a trick to riding a unicycle tho and it took me about a week to figure it out way back when i decided to try it. This was back before the internet, and before youtube, so it was all trial and error back then.
Currently i have a 24" cycle-pro unicycle, and I sold my 6 foot giraffe last summer.