I have been messing about with oars too, and it is pretty awesome to take a spokeshave to the shafts to get the shape, I have been gluing up, and experimenting with different woods. I have made a set of ash and red cedar, and a set of ash and cherry oars, I make my blanks, 1.75 inch squares x 9 feet long and then knock down the corners with a power plane. The cherry/ash are stunning to look at but stupid heavy, they have not been on the water, the ash/cedar are amazing, and are a ton of fun on the water.
I am using thickened west epoxy for the glue up, thickened with silica. I have handshaped the blades, but, it seems like many pro wood paddle builders are using a 6 inch grinder with sanding disks to shaoe their paddles