Is it possible to use the AngleMaster Wm-200 to set the angle when sharping/shaping a roughing gouge?
Possible? Yes. Handy? No.
But, the exact angle on a roughing gouge isn't critical. Use the check angles (the cuts around the outside of the WM-200) to determine the current angle. You want it around 50 degrees. If the bevel is too long (most common), shorten it up a little bit from the current, then gain a little bit on it each time until you get it to 50 or find your own personal happy angle.