69 Dart rearend

I'm currently mini-tubing my '69 Dart and will be having to research tires/wheels/narrowing in the future.
In all my research a 12" wide tire should fit into the mini-tubs. I have the US Car Tools Level 3 Chassis kit already installed, but I will not be doing the spring relocation kit into the frame. I can't see cutting up my frame for that. So when the time comes I will be custom fabbing mounts for my Gerst triangulated 4 link setup I have waiting to be installed once I'm done with my second tub I just started. Following thread to see tire/wheel setup responses.