I would suggest considering cutting the seal, installing it around the mast, etc. and then using some sort of silicon adhesive to seal the cut. I have used industrial razor blades for this in the past - they give a clean, precise slice that seals very invisibly.
It is a simple tear down. mark the parts in sequence as you disassemble. Good thing by doing that you can inspect, clean and lube all the parts!! I tore down a tilt column to restore and paint,.... found out that I needed to replace a few small parts but mostly did a really good cleanup!! Don't forget the seal before the linkage!!!Looks like new