Wow. All that, and then your question is not one we can likely answer well.

I only know a little:

1. Mil sizes are not closely correlated with quality or durability.

2. Only a few companies are associated with consistent quality. Plastimayd is good, but expensive. Tara is not usually junk.

3. Availability is somewhat regional. You can get a non-regional liner, but it will cost more proportionately.

4. Dropping liners into concrete pools is tricky. You may want to hire it done.

5. Repairing badly cracked concrete pools also takes skill and gear a homeowner will likely lack.

6. But . . . people have done it themselves successfully

If you want more info, post pictures (Photobucket, Picasa, etc.) and wait. Those of us in the pool business will get some relief starting the week after the 4th.