Rude Health draft tape part

This is a first draft tape part for a piece I'm writing for tape & 4 improvising pianists. It will be played four times, each by a different pianist to observe the differences and similarities between performances - what stems from the provided materials (graphic score/tape) and what comes directly from the performer's experience?

I'm looking for feedback from improvisers - specifically, there's more melodic material in this than I'd planned - would you feel tied in to the minorish tonality in the tape part, or do you feel there's enough scope to allow for a lot of personalisation of the part?

Also, the piano starts before the tape sounds - would this be problematic?

Any other comments?