Beautiful. You don't use pre-marked board. Strathmore bristol? Smooth or Vellum.I'm using 8-1/2 x 11, 60 lb. I can't scan anything bigger.
Use whatever works for you. There are no rules, and I've used a smooth bristol board for years and then the formula/papermaking process changes and the board bleeds when I ink on it. I just changed to pre-marked boards(whatever is on sale). So if something works just stay with it.