Stovepipe, build your shed with a door high enough to just drive in. In the next 10 years, you only need to forget _once_ and will spend more money in repairs than what you save today.
That totally ignores the issue of all the time to fold & unfold the rops week after week.
What if you get a different tractor or a backhoe or a snowblower (spout is much higher than we think!) or you want to carry something into your shed with a loader or carry-all?
You will often, many times over, regret building that shed door less than 8.5'. This requires a 10' wall most of the time.
I would do anything I could to make that shed tall enough. Do it right the first time. (And, whatever square footage you make the shed, it will be too small of a shed in 12 months.... /forums/images/graemlins/wink.gif ) But if you make the door high enough, at least it will be useable. Out here on the farms, we have many sheds that would be good, but are unuseable because the doors are too small to get anything into - our $$$ equipment has to sit outside.
Please don't make that mistake. It is a costly one.
--->Paul