I like the one that improves abi1 to generate 35 burst instead of 20. Then you can use Michael's San Michel and that on the same turn as PF to burst right away, without needing to spend your ex slot on that future skill that's functionally San Michel. (as I'm in the position of needing that slot for sniper shot in my own light Shingen team)
Also, it's not a big deal, but it would personally bug me to waste the +100% burst damage on AW Michael's San Michel if you use Shingen's HP weapon to change PF to +500% burst damage.