It was a blast! Thanks for posting this... I hadn't seen it.
We spent about 25 minutes in formation with Bruce and Jim, and just holding position while level was fairly physical. I found myself tense on the controls, which after all the hours of formation I've flown, was kind of humorous. Overall, it was very different and a magnitude more difficult than flying formation in a T-38.
They also shot some video, which I have.
BTW, the pilot in the backseat is Kuma, another regular on this site.