Just to update folks who may be interested , I have both chain plates removed. Both are in pretty good shape with only a very minor pit or two on each one. Not deep and I have no reservations reusing them. A couple of the bolts on the starboard side fractured ( from severe crevice corrosion) on removal. There was increased moisture ( from meter reading) in the bulkhead on the port side only which I have now dried out.
I’ve hogged out the deck core around both deck cutouts and the screw holes for the cover plates and filled the cutouts and the undercuts with thickened epoxy. When we get a couple of nice days I’ll recut the deck slots and reinstall the chainplates.
As for the rig, I tied halyards to padeyes on the side decks but the lines are not very tight and likely given the keel stepped “tree trunk” of a mast not even necessary.
I was really pleased the chain plates themselves are ok and I feel the job was well worth doing to inspect them and the bolts and the bulkheads that hold everything together.
I asked my son to add this to his diary to do it again in another 30 years. Haha