i'm going to cast another vote for having a private teacher work on this issue with you.
....however, i will offer some rambling for you
.
I was at a Bert Truax masterclass and he made a strong argument for strength of corners, saying that 'the more corners you use, the less pressure you need to use'. (Maybe some of the professionals on the forum will agree with that, maybe they won't)..nevertheless, that's been working for me this summer. So perhaps some exercises to strengthen your corners will help you to rely LESS on chops alone, and hopefully, avoiding unnecessary tension. (pm me if you want a suggested excercise, it'd take too long to explain right now on a post.)
Also, i would suggest the James Stamp book. Majority of the studies in that book expand your range in BOTH directions in one breath. Helps you break the habit of having a different embouchure set up for each register. Great Book!!