My suggestion, bring the spirit HP set ac equal to the spirit STR set, and bring its int requirment to 160.
OR
Bring the HP requirment of STR hero/valk/legend/spirit to 130-150 so they hace to sacrifice Damage for tanky mode.

thought about the 160 int on Spirit set
but

since it is so easy to get Hero Armors (often see them in merch for <100m)
It isnt really neccessary to have some kind of 2nd Int Armor on the server.

I think it might be okay to keep Spirit Armors as an alternate option.
So BPs with 145Int can switch on them and Int Priests might use them vs Mage Partys.

But I would reduce the Spirit HP Set Defense by 50 AC.
And I would increase Spirit Str Set Defense by 50AC.
So they will both have 870 AC in total.

Dont see anyone using Spirit Str Set atm...it seems useless.
Thats why I would increase stats on Spirit Str and reduce the HP requirement to 90.
It would be an option for the BPs that go 255Str and want to switch between Trial and Spirit Str Set.