You could build your own rudders and it is not too difficult. My wooden rudders are 4 oz. heavier than the original fiberglass ones. Simple use the old ones as a template. Buy two pcs. of Mahogany 13" wide, 37" long and 1 1/4" thick. Which cost me $63 ten years ago. Lay the old one on top of the wood and trace it. Now, cut out with jig saw. I cut my 1/2" longer and wider...you can always trim it smaller and as the end wears, you can reshape it. Next, I borrowed my brother route table...very cheap setup that worked great. Use a bullnose bit on the top area and more of a "knife" bit on most of what left. Next, I borrowed my buddies grandfathers large rasp....20 minute later..one rudder was ready for sanding, fiberglass and painting.
My only regret was not building an extra set because the time spent fiber-glassing and painting one side at a time was minimal in relationship to the cleanup time.
If a wood finish is fine for you....you can build yourself a pair of "prototype" very quick...and learn as you go.
I did have four Teflon bearing milled that I glued within the wood were the bolts pass through. No wear or friction at all.
Spares are nice!