I think your boat may use the same rudder/bushing as my Impulse 26. My boat is currently out of the water. I’ve felt a bit of side to side play of the lower bushing through the tiller so I dropped the rudder and lower bushing. Not only was the bushing to fiberglass tube very sloppy, there was quite a bit of wear between the bushing and rudder stem. I used a micrometer to compare the rudder stem diameter at various points along the rudder stem. I verified the stem did not have a bend in it. I removed the lower bushing from the stem and sized the inside of the bushing to the stem diameter where it would ride on the the lower stem. I also checked the clearances from the outer bushing to the boat tube diameter where the rudder passes through the hull. This was my problem.
It has been told to me that nothing will bond to the delrin bushing to hold it in place. You must use epoxy in the stem tube just above and just below the bushing when installing to hold the bushing vertically in place. On my boat the wear and sloppiness was in the tube. I will clean, prep, and build up the area where the bushing comes in contact with the tube with epoxy that will bond to the inside of the tube. Then I will use an automobile brake honing tool to gently cut to size and allow the proper clearance inside the tube. Reassemble. This is the fix I’ve worked out to be the best for me.
In your case, If you are determined to have a new bushing, you can have one fabricated, or there are many auto parts manufactures that have predefined specs often used for auto suspension systems. If one meets your needs, your done. If you want a custom exact fit, you will need delrin (recommended) stock and a fair machinist to turn it to your specs. There are several companies the sell delrin in various block forms. If it’s a large block, it will be expensive. You can purchase a smaller block segment or a segment of a delrin rod that can be turned to a precise fit. remember to spec to fit tolerances so the bushing will not bind. Googling delrin bushings or delrin block stock is a start once you have determined your specs. I hope this has been of some help.