Well, I'm a little disheartened. When I originally did my step frame, I hadn't made any plans to do any kind of SFBD, which I've been seriously considering since I have about six months of snow to look forward to. But, after disconnecting my rear shackles, I can see that my notch is about 4" short of where it needs to be.
So...do I go ahead and do the four-link then lop the frame forward of the axle and just scratch build everything back...or try to modify the step notch? I'm open to ideas.