-- Last Updated: Nov-01-12 2:08 PM EST --
The Courier is a neat boat but as Bob said, it is very deep, 15" at center and 22" at the stems, which makes it as deep as a full out whitewater canoe. That means it is going to catch wind.
I also think that moving the stock seat position is unlikely to help much. If your stern feels stuck in the current, moving the seat back will only make that worse.
The Courier is a shallow V hull without a lot of rocker, like quite a few other MRC hulls. Being a fairly long boat without much rocker it isn't going to turn on a dime. Shallow V hulls often turn much better if you heel them a bit away from the direction of the turn onto the "flat" part of the hull. If you need to turn this boat quickly, you are probably going to have to get comfortable with heeling it pretty aggressively.
Rather than getting a paddle with a longer blade, you might consider getting one with a longer shaft. You will be able to get your blade forward of the pivot point of the boat more easily.
With its great depth and small amount of rocker the Courier more closely resembles a downriver racing canoe than a whitewater river runner. The boat will handle some significant waves but you are going to have to plan your moves well in advance, and you may have more success maneuvering this boat with side slips and back ferries than you will attempting tight turns with draws, pries, and sweeps.