You can get up to vit+3 on kokugetsu sune-ate from the 5th place dominion trophies. Just need alot or to get lucky. I get about 500 chakra outside abys and inside I can push it close to 1k, depending on sub and atmas. Also make sure to go 4/5 or 5/5 on invigorate merits; the regen adds up.