The manufacturers have size guidelines that tell you whether the controls are suggested. Small children and elderly people sometimes need this option even on smaller shades. Usually there are multiple windows within a single opening, so you should usually divide up the blinds to line up with the windows. When you do this, order ONE valance to span all the headrails to make it appear to be one single product. See our section on the PowerRise.
Most people just make sure that the front products are generally white.
Most honeycomb shades have white backings despite their colored inside-facing fabric. If a stained room faces front and you're using stained shutters or wood blinds, then you'll have to decide if it's acceptable visually. Most think this is fine. The more symmetrical your home the more likely the products should be similar. Even good wood blinds are varnished and perform well under humid conditions.