Will be a bit biased based on how my LS's setups in these zones, but here:
Marjami:
Tucan Sam: Yoichi is great.
Hawakai: Works great but you'll need to stack r.acc.
Bats: Don't use, attack down is too severe.
Penquin: Shoha is better because you'll need to hold hate.
Harpy: Works great. (RNG mode)
Boss: Works great. (RNG mode)
Yorcia:
Eye: Shoha/Fudo better
Pitcherplant: Shoha better
Water Tree: For hate sake, use Shoha/Fudo but Namas works well.
Chloris: Shoha only.
Morta: Works great as melee or RNG mode.
Tree: Shoha only
Kamir:
Pig: Use Namas on correct phases. Shoha better for neutral.
Gnole: Namas should work, but I use Shoha so I can get hate. I use Yaegesumi on this one during Asuran Claw spam.
Coeural: Shoha/Fudo/Namas all work
Ram: You'll need to use both depending on mode.
Mirka: Namas works great.
Lion: Namas works great (RNG mode)
----
High Tier BC's: Namas with Sushi does hit on most of the BC's on D but sometimes on some VD battles, you'll need more than that. Generally, the damage won't exceed G.kat damage because these battles are too dangerous to utilize Berserk. Depending on the setups, I do find myself using Namas with berserk at the start of battles when hate is defined on someone else. Once I get hate once, I always take berserk off for the rest of the fight and depend mainly on G.katana WS.