Ever consider adding clethodim or Quizalofop for fox tail barley? Maybe not every where but on bad fields or spots. I have done it a few times and did it everywhere with my weed it this spring. Works great on grasses. Then can keep RT-3 rates down a bit. My rule of thumb is if 24oz/acre RT-3 won't kill the weed add something that will. Never been suggested that, just decided it myself. 24oz/acre is just under 0.75liters/acre. Foxtail is tough to kill down to the roots so it doesn't come back. Those 2 chemicals or iron have done the best job for me.
Then I just noticed slashnburn2 mentioned similar.