Jazz as a grandsire – temperament?

I’m looking at two dressage prospects, coincidentally both Jazz granddaughters. One is out of a Jazz mare, the other is by Jazz son Wynton. Curious if anyone has insight into how the Jazz reputation for reactivity and spookiness might show up with him a generation back, or with Jazz on the sire’s side vs the dam’s side. Most posts I’ve read discuss him as a sire.

The Wynton mare’s damsire is Negro. The mare with Jazz as her damsire is D-line Hanoverian on top.

Thanks in advance!

Do you have the ability to meet either dam?