While you don't want your boot to stick out too far, you also don't want it to be too tight. It does need to be fitted properly to provide comfort and performance. You can achieve the best boots and stirrups balance if you fit irons in the way that they are one inch wider than the width of your boot at the ball of the foot. When your foot is in place, you should have ½ inch of space on each side. In that way you can comfortably remove your feet for the stirrups when needed, while still having the perfect balance.