what to use as Ring 2 as War?

[Leiron]

All your jewellery should be HQ Gryphonskin melded with VIT, Parry and crit. More HP and nothing else is what PLDs should be gearing for.

You lose 25 VIT by using HQ Gryphonskin stuff, but you gain 45 STR, 45 DEX, some skill speed, crit and determination. For a Warrior it is well worth it.

Anything a Warrior can equip, a Paladin would equi.
You're giving up around 450 hp, just so that you can have a slightly stronger heal on your inner beast, a slight incrase on parry, and a very slight increase on crit and determination.
The 450 HP is far, far more beneficial for a Warrior than anything else.
Stacking vit is pretty much what you should do.

[Gamemako]

You're giving up around 450 hp, just so that you can have a slightly stronger heal on your inner beast, a slight incrase on parry, and a very slight increase on crit and determination.

Around 10% more healed from Inner Beast plus the additional damage and enmity, probably 1 tier of parry strength (405 tier), and possibly 3-5% parry chance (based on Ninjiitsu's data). It's a tradeoff either way. WAR won't be main-tanking turns 4 or 5 regardless, so I'm not quite sure how much it matters.