with the boat on the trailer or in the dry and elevated somehow, get the rudders pointed straight and have them deployed pointing downward like would be normal under sail. Measure the distance between the trailing edges of both rudders and then measure the distance between the leading edges of both rudders. The measurement should be about the same (some say 10mm of toe in is good - this means the leading edge measurement would be 10mm less than the trailing edge). Be sure your measurement points are taken at the same elevation in the blade - especially since yours sound like they are cambered outward (which is not a bad thing). To test if your weather helm is because of your rudder alignment, raise the windward rudder while sailing next time. If your helm goes away it's rudders. If it doesn't, it's probably a sail related problem.

Excessive weather helm is usually caused by an imbalance in the sailplan. Two forces are working here - the sails trying to pull the boat in a nearly sideways direction, and the hulls (and centerboards if you have them) grabbing into the water resisting that sideways force. The result is forward motion. However, if the center of lift in your sails is behind the center of lift of your hulls it will be unbalanced and the boat will want to pivot and turn. Your mast rake plays a large part in this because it will tilt your sailplan forward or backward and move the center of lift of the sails accordingly. If you are experiencing too much weather helm, and your rudders are aligned properly, rake your mast farther forward. A little weather helm is a good thing from a performance standpoint and a safety standpoint. You CAN rake your rudders farther forward to reduce the pressure you have to apply to keep the boat straight but this does NOT fix weather helm - it only aligns the center of lift of the rudders closer to their pivot point and gives you more mechanical advantage.

All this and a LOT more is in Rick's book - I highly recommend it.