About the ring chasing and the relation of issue to board. It is likely that a board will be cut across the rings, unless you look at a bunch and find an optimum one with stave like ring orientation. Some of us back the ones with "ring run offs" with fabric, silt for instance, which holds down the ends of the rings along the back. For your firrst bow actually, a $7 2"x72"x3/4" red oak slat from lowes or home depot works pretty well.
Dave