I'm 6' and like my 10' hammock. I had a 9' and it just didn't seem quite big enough. I could definitely sleep in a shorter one, but I just don't get as comfortable.

I have to echo the suggestions you've already received to get the longer fabric length and work your way down to the "proper" length. You can use the left-over fabric to make some stuff-sacks or hanging pockets or something similar.