I get all my incarnate salvage from TF, story arc, and trial rewards. I never spend Empyreans or Astrals on salvage, they’re worth reward merits. This means I both save the merits to spend on IOs, but running all those trials and TFs also means I make lots of inf, too. One character, all T4 incarnated out, typically earns enough merits and inf to outfit three or four alts with IO builds.