I honestly despise the current model of forcing Central teams to play at basically 9pm local in service to having proper "doubleheaders".
To me, there are basically 3 target audiences here:
1- fans of a specific team, who will only watch their team (in which case, playing 2 hours after 7pm local is a disaster)
2- fans of playoff hockey in general, who will want to watch as much of every game as possible (meaning the games should be staggered, not all at the same time, two times each evening)
3- casual fans who might want to watch a game if they see it on (so the specific time doesn't really matter, it's more about avoiding clashes with other programming, especially other sports).
The doubleheader approach doesn't serve any of these audiences. Why not just do it like this (assuming 4 all-Eastern series, 2 all-Central ones and 2 Pacific/Mountain):
2 Eastern series that start at 7pm Eastern (1 each night)
2 Eastern series that start at 7:30pm Eastern (1 each night)
2 Central series that start at 8:30 Eastern/7:30 Central
2 Pacific/Mountain series that start at 10pm Eastern if in the home team is Pacific, 9:30pm Eastern if the home team is Mountain
Seems more ideal