Pete,
Used both of those plus others. Like them both. The hickory will be noticeably heavier than the ash. Have also made them from walnut, black ash, paper birch, hard maple, red elm, and norway pine. My personal favorites are the black ash, and walnut just because of their good looks. But when the arrow hits the critter, you wont go wrong with either of those choices. JMO
By the way all of mine are 3/8" diameter minimum.
rich