Well, for starters, this is only my opinion on the topic.
Sticking to era correct, you will probably have a 5 or 6 gear Suntour winner freewheel that was offered in several gear combinations up too as wide as 13/ 32 ( pretty sure but just going by memory which sometimes isn't correct). That said, wouldn't it be great to have a nice 26/38/48 spread up front. Figure out what you use on your regular steed now, then interpolate how you are going to ride your klunker and adjust here:
http://www.sheldonbrown.com/gears/
I believe the reason the TA's were used on the original klunkers is because they were a good choice in a triple chainring setup for the time. In my opinion, if you are not going to use the triple rings, there may be other crankarm choices available. I knew on the DX build I was using an internal hub with a single ring up front so didn't feel the desire to use TA's. Looking at vintage cranks of the era, I had never seen Campy Pista's on a klunker (I am sure someone has done it, I just haven't seen it yet) and wanted to do something different. I think the Campy's came out looking sweet and era correct with a 1980 date stamp.
Back to the original question. These things are just Challenging enough to Acquire that I would adjust my build to whatever rings I could get my grubby little hands on. I do have put aside a new 52 tooth TA ring along with new Bullseye middle and small ring (Bullseye used TA bolt pattern on their original chainrings). The Prewar C frame I am currently gathering parts for will have this setup. Being tall, I would love to find some 175 or 180 TA Crankarms. TA had a large spread of rings available while they were being made. The pickings are getting slimmer and slimmer all the time.
Grab the good ones and put them aside.
Hope this makes sense
T