I have a very basic question about the correct placement of cabinet knobs. These are to go on raised panel rail and style cabinet doors made with 90 deg. corners. Is there a general rule of thumb for knob placement? Should they be over the rails or the styles? I know it's mostly personal preference and ergonomics but I would simply like to know what the standard is? This is a tall bathroom cabinet with two sets of french doors (two top,two bottom). The doors are 12.5"x48" and 12.5"x37". They are very sturdy and have good hinges, so there is no flex noted when pulled at the top or bottom corner. Please advise. Thanks.