I agree with Mark that a larger door opening would come in handy if you wanted to park your tractor inside. My door is 10x10, and it works our real nice.
I also noticed that you have a 2ft 10in opening for your door. I wasn't sure if that was the rough in opening, or the finished door size, but either way, I would seriously reconsider this and install a 3ft door. My doors are right next to each other, just like yours, and even with a 3ft door, I sometimes wish for a larger opening. If it gets really bad, I just open the big door, but for just carrying stuff in and out, I'd much rather just leave the big door closed.
Eddie