It looks like Dan has got you sorted with software that will accomplish what you want to do with your old master files. That's a good solution.

< Try importing a song with chords in open special and you'll see what I mean.>
I did take time to do this and found nothing surprising. I was able to replicate your project and used the Open Special with an original song I recorded in a commercial studio in 1975 with a live band and recorded without a click track.

From the time I opened BIAB, imported the file, ran the ACW, analyzed the Chords, used the ACW to create a tempo map, Found a suitable Style and everything was complete and accurately synced in just a bit over six minutes. That's not a reflection of my skill but is a clear indication there's no issues with the ACW working correctly.

I've attached a screenshot showing how just ensuring the first four bars were precisely aligned and placed manually, allowed the ACW to set fairly accurate bar lines for the remainder of the song using the Auto Marking button and only a few adjustments throughout the remainder were necessary to create a good tempo map.

< "I find the ACW won't even generate an accurate chord sheet." coupled with "I won't even get into in the ACW setting bar lines I've wasted more than a few hours on that." >
Accurate chord detection and analysis results depend very much on precise and correctly setting the bar lines.

Hopefully Dan's suggestions will get you quick results with your project.

Charlie

Attached Files (Click to download or enlarge) (Only available when you are logged in)
acw.jpg (192.95 KB, 23 downloads)
BIAB 2025:RB 2025, Latest builds: Dell Optiplex 7040 Desktop; Windows-10-64 bit, Intel Core i7-6700 3.4GHz CPU and 16 GB Ram Memory.