Ok, I've been lurking for a while and decided to post since you asked...
The number one thing that stands out to me, is your willingness to think outside the box, and that you readily realize that steel doesn't always have to be in a straight line
Nice use of curved materials. This is a huge undertaking, so I envy your determination and the amount of spare time you must have available. My only concern is what the total weight is going to be when you're done.