Double check that equipping one of the swords two-handed does not increase the enhancement bonus. If it does, you may want to try modifying the first eval script to:
if (tagis[Hero.MainHand] <> 0) then
perform hero.assign[Custom.TwiceEquip]
elseif (tagis[Her
ffHand] <> 0) then
perform hero.assign[Custom.TwiceEquip]
endif
That way a particular sword can only apply the TwiceEquip tag once.
if (tagis[Hero.MainHand] <> 0) then
perform hero.assign[Custom.TwiceEquip]
elseif (tagis[Her

perform hero.assign[Custom.TwiceEquip]
endif
That way a particular sword can only apply the TwiceEquip tag once.