Greg,
Thanks for checking in.
For your (assuming smallish) athlete who has Pad Y of 545 and Pad X of 463…the only option is a Small with the short stem, flat bar slammed. Without the TSP (Team Switch Plate) the shortest the pad goes is 466. I’d set it up that way first and see if the Pad X of 466 will satisfy. If not you can add the TSP then it’ll scrunch up the cockpit all the way to 439 so a few holes forward with the arm pad and you’ll get into the 460s.
Ian