Still using the same rudder.
The lamination between the two sheets of plywood in the blade was starved of glue and had to be reworked after the first season.
I refinished the blade once after repairing some minor dings from ground contact and also had to repair some cracks after the rudder was hit by another boat at the dock (hard enough to wrench out pintles and gudgeons).
Other than that, has worked fine for me.
I picked plywood because it has differently colored layers that make a pattern when you shape the blade. That was a great help in roughing out the foil shape. Also, plywood dimensions are in full / half inches, not some weird intermediate lumber sizes.
I used birch plywood with many more than the usual number of layers (5 or seven).
Did not use marine grade. You want some grade that has no voids, but once you seal in epoxy and encase in glass, there's really not the exposure that makes marine ply critical.
Since I have the factory rudder head and blade, I originally conceived of this as an experiment: can I create something with reasonable effort that is lighter and has better foil shape? I think I succeeded and find that it's standing up to some long-term use.
I use epoxy. Almost any epoxy (other than the H/W store stuff in the dual syringes) will work pretty well. I use SystemThree. Their "GelMagic" is the one formulated for gluing. You can get it in a caulk gun cartridge with self mixing tip -- makes it very convenient.
There's no point in gluing the nylon bushings other than to seal the drilled hole (the latter is important!). Doubt the glue will permanently bond with the Nylon.