I would explore the width-of-the-rim issue a little more. I started a similar thread a while back about my Schwalbe Big Apple 26" X 2.35" balloon tires. Having switched from 1.5"'s, I felt like the weight and mass of the wider tires were shifting from one side of the rim to the other as I rode along. Someone suggested I might be using them on too thin a rim, but that I might be able to compensate by adjusting my pressure. After a lot of experimentation, I found a good balance, and now I am in love with these tires. No more of that wobbly, off-balance feeling, which seems similar to what you described.
My advice is not to give up until you post this to the Bicycle Mechanics Forum and see what advice you can get there. Good luck. I know what buyer's remorse feels like, but I think you might find an answer that makes you feel a little or a lot better about your new tires.