I have found that exercises apart from actual drumming (like what athletes do) helps alot with the weaker limb.
Hold your leg out and flex your right foot a hundred times as quickly as you can with consistent motion. Try the same with the left foot. It should tighten up far more quickly. But you should find as you do that simple exercise, both feet will pick up coordination, speed and endurance as you easily get to 100 reps. It's just muscle development.
Another thing to try is just sitting down with a practice set up (if you have one) and play to music with just your feet doing whatever strokes you can. Follow the melody line, or vocal line, or just follow the bass or whatever.
As far as balance I found out a long time ago that office chairs blow away drum thrones for comfort and balance for me, especially using a back rest. You can find really nice old chairs at used furniture or office supply stores, or try a new chair that suits your posture.They cost alot less than a high end throne, too.
Lastly, I played dble pedal for almost 20 years and began to notice some real problems with discomfort in my hips, knees, and even my ankles. It's just the slight twisting of the body to accommodate the typical bass drum/dble pedal set up. I came upon the Fisher OFF SET dble pedal through a discussion board, checked it out, got one, and not only did all the body discomfort go away, but the pedal produced exactly the same action for both feet just by sheer design and the natural playing position it puts you in. I love it. Best pedal I have ever owned, and I've played many of them out there. Charles Fisher is a great guy, too. Check it out: