I believe I mentioned the stanchion issue when we met last spring..
You could probably shim them as you describe but you will end up having to redrill the boltholes because they will no longer align with the offset stanchion bases. Do you have good access below to all those areas? Also your backing plates should probably be matching wedges.
by UHMW PE do you mean material like 'Starboard' or 'Seaboard'? With care I think you could cut appropriate wedges with a larger table saw or cut-off saw. Getting sealant to stick to it could be a problem and the last thing you want to do is create more potential leakage issues. I wonder if a good hardwood wedge, epoxy sealed and properly bedded wouldn't be a better choice.
All that said, replacing or modifying the stanchion bases would probably be the most straightforward (though at this point finding matching bolt patterns could be tricky too)
How was the rest of your summer??
Thanks for your reply Ron. Our summer has been great, with a lot of DIY boat repair, sailing in English Bay, and a couple long weekends at Halkett Bay (made possible, in part, by a guide you wrote a while ago).
We've done all kinds of things to the boat; replaced cockpit locker hinges, repaired non-functioning bolt holding stairway, added netting, replaced endless furling line and rigged a tensioner and clutch system for effective reefing, replaced jib sheets, figured out the gennaker, added more thruhull clamps, reattached (properly) the raw water screen, removed the 6x CD changer (amp/preamp on the way), shimmed tiller higher than cockpit seats, retired the autohelm 2000, ordered a pelagic autopilot (should be here soon, so excited), got a headsail repaired, climbed mast to replace spinnaker block, replaced the dinghy, rigged a ladder that's easier for my dad to climb, inventoried everything and reorganized it all, treated water tanks...
I'm sure I forgot something
But yes, much work and much fun. The Saltire is a happy boat.
The old dinghy, The Saltine, found a respectable place in our garden.
edit: feel free to use this as case study for what you might have to do in your first year of boat ownership