4-Bar set-up question

I've been searching other threads on rear 4-bar set-ups but really couldn't find what I was looking for. I'm planning on using short links that I can adjust from 12"-14" eye to eye so I can tuck the rear axle in closer to the body. I'll be using a transverse spring. My frame rails are 29" wide at the rear. If I mounted the bars to the outside of the rails and ran the bars straight back to the axle, would that distance between the mounts be OK? The rear axle is 56" backing plate to backing plate.

12-16 inches would be fine. If top and bottom are parallel you will need a track bar (J- Bar). If you run the bottom parallel and the top triangulated to the top of pumpkin you will not need one. To eliminate pinion angle from changing dramatically during suspension travel top and bottom need to be parallel to one another. Now if you want to put forward bite in the care top bars can be a couple degrees uphill at the frame. I believe I have some pics on my thread of my set up. Hope this helps.

Annamel, thanks for the clarification on pinion angle.

If my transverse spring is set up correctly would I still need a panhard bar?

This is not a 4 bar but, is similar to what you're going to do so, you do not need a panhard bar

Old Iron is that a front spring mounted in the rear?

Sure looks like it.
This isn't something I built, just a pic.

Car I built a few years ago needed very short four bars, and quite narrow too. I fixed the axle brackets so the bars actually attached behind the axle, rather than the customary in front. It allowed me two or three inches extra length on the four bars.

I also mounted them to the outside of the frame rails, to give more width where they connected to the axle.