Pops,
I have a 4 link with a panhard bar on the '53 and decided to go triangulated on the Ranch Wagon. So I have done both, recently.
The parallel 4 link is much easier to lay out and make brackets for. Often it is also easier to find room for the parallel bars. When you're done you have a little bit of adjustment with the panhard bar.
What I'm running into on the Wagon is that the axle is centered dead nuts on the frame, but the driver's side quarter panel is farther out than the passenger side. The triangulated has no adjustment. It's a small thing, but if I had it to do over, I'd go parallel.