Originally Posted by CptnTantalus
...Unless you can suggest a Canadian source?
Catalina direct is as good as you can get, I suspect unless you have the right material and dimensions and get a local machine shop to make some for you.
Swollen bushings can be 'reamed' for clearance but it may take a couple of gos before the swelling's done. Easier/better to fix it proper.
The tide grid idea is good, but check to see just what clearance you'll need under the boat to actually get the rudder out...Sometimes you need to dig a hole under the rudder.... There are likely two bushings, an upper (at cockpit end) and a lower (where the post exits the hull)