My pleasure :) Yep, you could adjust anything to however you want. Could add more stalls, more hay storage, bigger tack room, bigger run in ... everything is adjustable when your building :) Just keep in mind that if you make the open area bigger, you need longer crossties. I recommend making a clipping mechanism so that you can clip the crossties to the wall when not in use, but that's something easy that your average joe could do.
Best of luck!! Let us know what you decide :)
I've had to store hay in my tack room because it was the only space available, and its not that bad, just dusty sometimes.