I always narrow the limbs on every bow I make as long as I have draw weight to spare , I never narrow into the fades I usually start my front view taper out side the fades and narrow equally I usually scribe pencil lines on each side of the limbs and take the limbs down slowly stringing & testing as I go ,the center never changes threw the riser, narrowing the riser can be optional it doesn't have any effect performance mass wise , it's amazing how much performance you can gain losing width but there is a point of no return to on each design to...lol