For an expanded league, I like this idea. Although it may be tricky for the races that have a pace lap.
I don't think it's the best idea. Final finishing positions in a race definitely need to be decided on the same track between the drivers involved. Losing to a guy that is running in a different race under different circumstances isn't right. I think it's best if all drivers know where they stand when a race is over, not have to wait for us all to compare times.
Imagine a guy beating you by 3 tenths of a second from the other race. Had you been on track with him, you could have drafted past him for that position. No one is going to like that.
Of all the options I've considered so far, I'm leaning toward holding two heat races and using those results to split the field into two main races.
The drivers in odd points positions (1,3,5,7,...,23) would roll out in Heat Race 1.
The drivers in even points positions (2,4,6,8,...,24) would roll out in Heat Race 2.
The top six finishers from Heat Race 1 and 2 would go to Main Race 1 and race each other for finishing positions 1 through 12 (disconnects would be moved to the bottom of Main Race 2).
The bottom six finishers from Heat Race 1 and 2 would go to Main Race 2 and race each other for finishing positions 13 through 24 (moving above any disconnects from Main Race 1 that completed less total laps).
I have also considered a split-season approach, where there are two separate races (again split by odd and even points positions) with two winners, and points given out for 1st-12th in both races independently. The top 8-10 drivers would all be combined on track together for the Chase only. But, I think people would try to avoid being in Joe's road course races, or ACDC's oval races, etc.
I also don't like the idea of having two people win one race, especially if they weren't in the field with the best drivers every week. Winning should definitely be special, and I think a two-race/two-winners approach takes away from that. I think having a 24-car points structure (points range from 28 points for 1st place to 1 point for 24th place) with one clear winner per week would make it more important to show up each week and perform well.