Doesn't matter. Company technically doesn't care so long as the plane is crewed 24/7. So you and 2 other dudes create a google calendar or however you wanna organize it and pick what days you want to work. Only "rules" I am aware of is no pairings shorter than 4-5 days, depending on domicile, and you have to overlap a day with your outbound buddy so you can take the plane from them when your rotation starts. Comes out to 12ish days a month assuming all 3 of you are on the same page and nobody has vacation/recurrent/ medical leave,etc....

It's on you to find 2 other captains and basically email the company and say: "hey, i got 3 captains, we'd like to be a Red Label team" and once your seniority can hold it, you're assigned a jet. My understanding is also that the team's overall seniority is driven by the most junior captain of the 3.