Kiln drying is just a controlled quick drying technique to prevent checking and twisting. Once the lumber sits in your shop it will acclimatize to your R/H then its is just like any other. The board will determine whether it needs backing or not. Backing makes not so good wood more suitable for bow making. There are many backing materials that run the range from brown paper grocery bag to silk or linen to hickory, maple, elm and bamboo. Let the need decide the backing. If you are just trying to help a perfect board, brown paper, silk or linen will do the job. If you are looking for more get-up and go, the wood and boo backings are what you want but be sure to match the backing to the belly.
Most bows are made from relatively straight, knot free wood. Any deviation from that would be considered "character". Twists, knots, hoop-te-doos and snakes all add character to a bow. Pat
