My Stereomour II kit was short by three # 6 shoulder washers. I ordered some from Mouser but when they arrived they were big for the holes they were to go in. I think the opening was the right size. Apparently there are more specs that I should use to order these washers. Mouser gets my orders to me the next day so I prefer to source from them. What are the dimensions of the # 6 washers specified in these kits?