But your elbows really need to be by your side, not flapping about.
If you concentrate on that, you can indeed soften your hands. Our RI told us to imagine we were holding a newly hatched chick.
I have to say it is so long since I had the luxury of riding without stirrups or sitting trot that I am hardly one to tell you what to do. I share a horse who comes with baggage attached. A whole lot of things "She does not do" because she is said to be such a bumpy ride. And I have to take notice of that.