The new sheave was a perfect fit. I printed it out of PETG-CF (carbon fiber embedded). To smooth out the layers, I put a bolt through it, tightened it down, put it in a drill and took some 240 grit sandpaper to it. Two minutes later it was fairly smooth.
We went out last night and the admiral was shocked at how much easier it was. She said she didn't have to put the sheet on the winch when unfurling the sail. I think there's still room for improvement but this is a huge step forward!
I have the backstay adjuster set about half way at the moment. I can play around with that. I definitely think that the stanchion blocks could benefit from some lube. I also replaced the severely worn plastic fairlead with a metal eyestrap on the camcleat. This likely reduced friction.
With no load, the bearings spun fine but we all know how that changes once loaded. Soap and water might be a good idea