Bridle length? I generally make the passage for the bridle 3-3.5 inches behind the prod socket... some medieval bows make that distance a bit shorter. Diameter of the hole, @ 3/4 inch, but it depends on how much cord you use. I normally flatten the passage (hole) at the front and then bevel its edges, because that makes the cord stack more compactly and keeps it tighter over months/years of shooting. Many central European bows use a flat-fronted passage, but lots of western or southern bows use a round hole, simply bevelled on the edges. Length of cord: I normally use 6-7 fathoms of 140 lb. cord (about 4 mm diameter, it's the heaviest I can get online) I usually don't wax the bridle, but if you choose to do so, there are special liquid waxes used by shoe makers that should serve very well. Your mileage may vary. Geezer.