I'm not ocd about stacking stam, but I've always felt as a tank there are only 4 (or 5) gems to use:
I never gem dodge/stam and I don't bother with hit/stam, although given how high my defense is, I might change my mind about that.
But rather than getting into an avoidance/threat/stamina argument the real solution is... keep both weapons.
Gem peacekeeper with some stamina and give it bladeward/blooddraining/mongoose and enchant Legacy of Thunder with accuracy or ye old weapon chain.
Swap out weapons accordingly. The avoidance difference between the two is negligible. But the threat (due to Dwarf racial) and EH (due to socket) difference between the two are not.