6BSAlmost looks like the 12" rim makes the tire wider. I am in the middle of this same project using wolfe mini tubs, and had the 9" shortened 2.5" on each side. when you find out the back space on the 12s for sure could you post that please.
Was leaning towards the billet specialties myself now I know they are for me.
Cars look fantastic, thanks for sharing and keeping me geared up on my project.