Be careful! Kodak's recommended times for Tri-X and Plus-X in dilution B are dead wrong. These crazy three-minute times are for dilution A, not B. It is either a misprint or a mistake in testing, but whatever the reason, it has not been fixed for years, TMK.
Check out Ilford's recommended times for Tri-X 400 and Plus-X in their Ilfotec HC developer at 1:31 (the same as Kodak's dilution B), and that should give you a starting point, since Ilfotec HC and HC-110 are effectively the same developer. There is no way in hell that the time difference for a film in Ilfotec HC versus the same film in HC-110 could be as great as the published differences are (around three minutes difference). Also, note the similarity of the recommended times for Tri-X and Plus-X in Ilfotec HC 1:15 (the same as Kodak's dilution A) to Kodak's recommended times for Tri-X and Plus-X in HC-110 dilution A. They are near identical.
All these comments apply to Tri-X 400 only, not Tri-X 320.