Static driver sitting position during the season.
Since this is a series where you stick with a single car for entire season and I don't see why this rule couldn't be introduced in a multicar series as well, it would go with your name, realistic, to have every racing driver pick which side of the car he will sit in his brand new car at the race one and then stick with it through the season.
Swapping left and right between the races not only makes it unrealistic, but unfair towards drivers who use cockpit view vs free or follow view and in a tight competition as your series it might turn out to make a difference. You could argue that it takes skill to adjust from driving on one side of the car to another, but this only goes as long as it's cockpit view and quite a few drivers don't go thru that process and rather rape full benefits with other view settings. And you can't argue that cockpit is the fastest view in order for swapping sides to be justified, because it simple isn't. It's only the most enjoyable and as fast as any other. I say most enjoyable, because it's by far the most challenging for spacial awareness within a close battle.