It's worth pointing out they only need three sets of kit. Yellow with sponsor A, yellow with sponsor B, and black with sponsor B.
If they were doing a 50/50 split they would probably need half the away games with sponsor A though. So 4.
With yellow shirts being viable on the road in all but a couple of matches, you don't need black shirts with both sponsors.
But also, at least as it was explained to me last season, the only snag is 50/50 across the season, not also 50/50 home/away. The reason they can't achieve 50/50 across the season just by going 50 home yellow/50 away black is because black clashes with a lot of other team's home kits. That then prompts the crossover.