Well, since you asked twice!
Perhaps the problem you are getting tense in the right hand is that it is too heavy, and too uniformly loud. I think two things need to happen here: one, the left hand has to be played with much more creativity, and less monotonous accents. Second, you should embrace the character of the piece rather than seek to increase speed. For me what is missing is a sense of enchantment, a sense of fun magic and that kind of imagery.
It has to be much softer, and also have more variety of tempo, and have variety of sound. Although you observe the dynamics on the surface in the left hand, the right hand doesn't change much. It's loud and a little bit less loud.
You don't seem to have many problems with your technique so I am sure you can handle this.
Walter Ramsey