I've found that aikido practice has helped a lot with regard to use of both hands, since we usually train all techniques (except bokken) equally from both sides. This is true for both open hand and weapon takeaway techniques and drills.
Oh, I also fly from either side of the cockpit equally well, with stick or yoke, doesn't matter much.
As a result, I find that I can do most things equally well (or nearly equally well) with my left hand. However, I can't throw well with my left, or write all that quickly or legibly.
I'm working on left handed pistol shooting. Haven't thought much about left handed rifle, but I suppose I should try that every so often, too.