Yeah... They're a bit... tight!
But didn't you sit in it, before plunking down the cash?
My Missus is 5' 1", and I'm 5' 10": we noticed it, and decided that it was a "workable" ride...
But I DO realize that everyone has their own personal comfort levels, so have fun with this project, and we'll be interested in seeing what modifications you make!
Good luck!