Improv drawings to jazz

An interesting proposition came to our art group--to paint while Michael Arnowitt played improv jazz, but not just in private. We will be painting while Michael plays a concert at Wood Art Gallery. He has written a grant and been awarded some funds for this event now scheduled for July 12th. To warm up I went to his last concert where he played his own compositions with his 5 piece jazz group ImproVisions and these are some of the resulting drawings. I was seated within the audience for this concert and limited myself to oil pastels on ancient colored paper and pages from an old art magazine which was quite experimental and exciting in itself. So enjoyed the music and my working with it. Like I was an instrument or dancing. I "played" until the end and found myself so exhausted after the output that it was hard to drive home. I was spent. The 3 of us who have promised to "paint" for the concert got together another time "to practice".
I'm quite certain that there is no real way to practice for this event. It will be a happening thing and I hope grace and inspiration are with us and no great mishaps occur. How can one practice for improv?