The smaller the numbers, the more that favours Shin. He has the stronger officers and their impact is more notable and impactful on smaller battlefields. The Kyou Kai Unit would've made this a nightmare scenario for Kei Sha before they added Kyou Rei. Round 1 is, I think, a crushing victory for Shin.
Round 2 is more interesting because it's Shin playing with bigger numbers than he's ever had command of, even if you include that time he assumed command of the right wing at Shukai. That said, Shin has Ka Ryo Ten and Kyou Kai, the former is a prodigy of tactics and strategy, and the latter a 6GG talent rapidly catching up and well primed for a generalship of her own - the numbers just aren't big enough to make this too much of a challenge for Shin. If anything, the numbers suggest Shin might actually have the space to maneuver around the battlefield and tap into his own Instinctual Prowess - which by now have surely surpasses Kei Sha's own.
This is an interesting match up, but one that plays too well to the HSA's many strengths, imo. I don't see Kei Sha having much luck in either scenario.