- Terra Helmet (7%)
- Earthheart Cuirass (8%) / swan feather cloak (12%)
so 15% is your "permanent" damage reduction if you go with cuirass, 19% if you go with cloak.
You can imbue a shield with Snake Skin t3 for extra 15% for 20 hours and use the shield only for scarlett adding up to 30% or 34%.
If you use Terra amulet u get extra 20% with 200 charges, Sacred tree Amulet is 40% with 5 charges, problem with sacred tree is it blocks physical as well so its gonna get wasted every 2-3 turns, the Terra amulet will probably last more than enough time.
I believe 50% (cuirass + terra helmet + imbue + terra amulet) should be more than enough to feel safe.