With a pool from the 1960's, you might want to see if you can find a rehab contractor who (a) has a 5+ year track record of successful redo's and (b) will take on the project of restoring your pool to full function. Trying to fix this and fix that, you can end up with a lot of things fixed, but still have a pool that doesn't work.
If the contractor is bidding on restoring a working pool, rather than just a refinish, he'll tend to 'dig deeper' in his investigations.
Both FG and plaster can be used, but success rates depend on contractor skill and integrity. In particular, plaster does NOT guarantee a stable shell that won't leak. If you want more info, take a complete set of photos -- pool, deck area, equipment -- and either email them to me at poolforum@gmail.com OR post links to the photos on Google Drive, Flickr, Webshots, etc.
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