My Indoc class in April had 18 DECs and 2 FOs, but when we got to systems we had 18 DECs and 8 FOs bidding for sims together. We had 5 CA/CA teams and 8 CA/FO teams. The group a week ahead of us were all FO/FO teams. I was paired with another captain and we switched seats halfway through each lesson and alternated being first. You get right seat qualified during training as a DEC anyway. There's no way of predicting how sim pairings will work out in your class.

Ground training is the same for captains and FOs except captains get an extra two days of ground on the duties and responsibilities of captains. They want everyone to learn both captain and FO flows. Captains are held to higher standards in the sim.