Maybee 3/16" crown is nothing to worry about?

My answer is; it's a carpenters choice. Any of the previously mentioned options will work also treating the plate as straight will work as well. First, the crown will be bearly visible. Second, slight mid-span crown looks good but slight sag never. Third, the geometry with the crown is very close to ideal. Assuming otherwise straight and square material and a 12 ft. plate to plate outside distance. With a 3/16 crown, the outside dimension increases to 144.00012 in. The slope of the rafter plate seat deviates from level plate top by .001302 per inch. The ridge will rise by 3/32 and will shift slightly away from crowned plate, amount depending on slope. So in practical terms the deviation of geometry is within normal tolerance of construction.