Battle of the pretty boys of Qin and Zhao
Seika: 100k with all of their commanders including Ji Gag and Jokeareyou
SHK: 130k
He gets the black cavalry and some of the non vassal generals:
Remaining Kanki army, Heki, Mouki, Fuu Han and Ju ko'Ou who was captured.
Battle at Shukai plains.
This is the opposite of the Moubu vs SBS matchup. SHK can possibly take it mid-diff, but just to play it safe I'll say he takes it high-diff. Reading your other post, originally you had it be 100kvs100k, so I'll base my answer on that scenario.
Shouheikun vs Shibashou as generals:
Martial Might: While Shibashou maybe a better fodder control person and superior in raw physical stats, SHK in a mano e mano could possibly win or push him to extreme-diff. The feat that SHK pulled against the Duke at State of Ai arc was absolutely insane, the Duke is listed at strength state 89/90, akin to Yotanwa also neg-diffing one of the brothers in WZI who is listed at 90. So his "real" strength stat should be somewhere near Yotanwa's atleast. I'll give him a 95/96 stat as a base to work off of here.
Then we come to weight. Firstly, we have the weight of a general which is based on the amount of life one carries on their shoulders be it allies or enemies, just as how Kanki said the death of all those who die in the unification is on Ei Sei's shoulders, the deaths of those who the Qin army kills based on SHK's strategies is also on SHK's shoulders. This is where SBS will be lacking compared to SHK. Secondly, weight of the unification goal... the unification goal is something SHK has been working on before Ei Sei revealed it to be his own goal. SBS as far as I'm aware has not shown that grand of an ambition. Keep in mind, Renpa & Ouki blatantly found Gaimou to not be worthy of their time due to him missing a grand ambition that would bring out his true prowess.
This is of course not to say SBS won't have any weight himself, I'm sure he does with relating to protecting the people of Seika. But just that SHK's will be bigger.
So I don't think the martial gap between the two will be huge, and with SHK POSSIBLY being able to pull out the W dependent on the weight factors.
Strategy: Heaven and earth apart.
SHK is just a superior overall general. Martial might can only overcome strategy when it is far above strategy. Otherwise you need the combination of insane martial might & some strategy to conquer high end strategy. Sadly, SHK doesn't allow SBS that privilege.
Commanders:
I'm assuming you're giving SHK his known vassals atleast and not just his special units commander Hyou Shiga. I'm going to base this on the assumption that you are doing that.
SHK will effectively have: KaiOku, Kou Ryuu, Hyou Shiga, Ju ko'Ou, Mouki, Heki, Fuuhan
SBS will have: Kansaro, Jiaga, JKR, Fuuon, Gakushou,
I'm going to rank the commanders from the best to least:
1st. Juko'ou
2nd. KouRyuu
3rd. Kansaro/KaiOku
4th. KaiOku/Kansaro
5th. rest you can debate too lazy to rank.
However, just among there, there is a GAP between Juko'ou and anybody else here. We're talking about great general who essentially commanded over Man'U/Sentou/etc with his strategies. His equivalent would be somebody like Genpo. Nobody on Seika's squad is even sniffing Juko'Ou as a commander.
And as for KouRyuu, the man was the "main general" in Ei Sei's army that he brought to deal with Kanki. Hara had him be name dropped by Ei Sei himself telling SHK to call up KouRyuu. His strategical synergy with SHK is amazing, the man without a single word executed the strategy with SHK and Ten. And you're going to now scale that strategical synergy on a much bigger scale.
While people have multiple times mentioned the strength gap between the two armies nobody has brought up the VAST strategical gap between the two armies.
The situation:
As I mentioned earlier, martial might overcomes strategy when the strategy is mid and the martial might is overwhelming. Or when Martial Might is paired with a solid strategy. (Before anybody mentions the "stalemate" between Karin/Moubu, Karin had never planned on an actual invasion into Qin, and their clash ended right when Karin was actually about to implement a strategy).
And, great martial might can overcome great strategy if the scale is small. Because the strategies are limited at that point However, once you expand the scale of the armies & the location, the advantage for strategy is completely absurd. Hence why you will never in this series see Moubu doing a war by himself or if he does do a battle, it'll be very small numbers or a simple one. You will also never have him be the main general who plans out an invasion vs a high-end strategist.
Otherwise, what happens when you have great martial might vs overwhelming strategy... is you get Ordo vs Ousen. Where Ordo has the superior martial might of an army + superior numbers, but has absolutely nothing to counter overwhelming strategy with.
With a battlefield like the Shukai Plains that does have some hills around it along with the huge size of the battlefield, who then add on 100k size army, where SHK can implement damn near any strategem he wants, and there's not a single person on the opposite side who'd be able to comprehend the shit he'd be doing. And unlike Ousen, SHK himself can execute assassination strategies himself like Riboku did with Makou, except on a bigger scale due to his martial prowess being higher than Riboku's so far. Adding on to that the strategical synnergy between himself and 3 vassals.
Adding on to that Juko'ou himself can strategically mindfuck the Seika army, let alone when combined with SHK.
Honestly, the more i'm writing this out... yea SHK clears this mid-diff.
TBC: If the scale of the battle was smaller... like 20k vs 20k / 40k vs 40k, I'd give it to Seika no doubt. Different generals are just suited for different scenarios, somebody like SHK is just a monster in a scenario like this.