Determine a tentative stance width.
The goal: (Again, as it bears repeating) To stand equally weighted on both feet on the dynamic midpoint of the board, with full mobility of the joints of the lower extremities, hips facing the angle of the front foot, with an absence of muscular tension. (Notice that the CM in the following photos is between the feet by default, without postural contrivance).
Because of the number of variables involved, the stance width you start with may not be what you end with. Remove the footbeds from your boots and set them on a flat level surface. Stand on them, and find the degree of knee flexion where your knee joint will ‘facet’, (see section 4). Ask your henchperson (the one you keep on hand for such occasions) to match the angle at the back of your front knee with a carpenter’s bevel gauge (insert photo here). Turn both footbeds to match the angle of your front binding. Maintaining the gauged angle of your front knee, with the tibia of that leg more or less vertical, gradually slide your rear foot backward. When your stance becomes too wide, you will develop tension in the quad region of the front leg, your hips will rotate away from the direction of the front foot, and/or it will feel like you are no longer standing with equal weight on both feet. (If you know that you have limited dorsiflexion, particularly in your rear foot, take this into account when evaluating weight bias). Find a stance width that accomplishes the stated goal, and carefully step off of the footbeds. Measure the distance from the midpoint of one to the midpoint of the other. Use this as a baseline stance width. You might go wider; you might go narrower. With all other factors taken into consideration, if the stance is too narrow, you may feel a lot of nervous tension in your legs when the board has ‘powered up’ back on the snow. This is the effect of your body stabilizing itself on a springy platform with a base of support that is too small. Widen your stance by one centimeter and try again. Do not move the front binding to change stance width (move the front binding to change board response). The first sign of too much width is premature fatigue of the front leg quadriceps. There are others, but front quad tension provides the most obvious feedback for the rider.