What Pitman arm etc do I need for this setup?...

Yes, I've searched the forums and read a bunch of threads about power steering to manual conversion. I'm still confused, sue me! Lots of people seem to be confused in those threads, adding to my hesitation. I already know I need the PS to manual column adapter (or a new column).

I've already bought some parts for my car that aren't even going to work now for various reasons, so want to get this decision right!!!

My Setup:
- '70 Dart 318 car with a/c, so has stock 10" front drums.
- Installing '73 11.75" front disc brake setup. I have upper (and lower) control arms, pretty much everything but the pitman arm.

Questions:
- Do I need to find a -'72 Manual steering box? Or can I use the later manual steering box? (Some say it matters, others don't... I want the answer from someone who has done it!
- Since I have the '73 discs, do I use a '73- pitman arm? Or '-72?
- Is there anything else I need to change from my '70 setup? Idler arm...? ???

Thanks in advance.