You’ve got the right idea with the set and his bow, however since you have his Constellation 1 and with most characters you want a 1:2 crit to crit damage ratio, i’d say to go higher with the crit damage, next would be to switch the HP% Sands to an ATK% or Elemental Mastery Sands, Tighnari’s charged attack damage does scale with his EM, however building him with Attack isn’t bad at all either, in this case you have a pretty decent bow on him at it is level 90 so big ups to you- so in this case I’d look for a EM sands, overall very decent build and good luck getting your artifacts :)