I've made a simple note definition to show me last 5 showdown hands of certain opponent.
Very simple, shows as "[ $cards ] $pfposition vs. $enemypfposition" and can be replayed for more info. I dont use it as general NC popup ("Show in the notes popup" is not ticked), but it's connected to a popup of one of my stats. Number of hands stat actually.
In the HUD Options I set up "Use last X opportunities" as 5. But it just shows everything, so I get huuuge popup over my whole screen if I click on someone with a lot of hands.