About 9 or 10 per cent will work for just about any bowwood. Some woods prefer a lower and some prefer a higher content. Hickory likes dry...below 8% is best, even 6% won't hurt, while such a low EMC is dangerous for most woods. Yew can tolerate a slightly higher EMC such as 12%. But you really shouldn't want that...
Low EMC makes wood brittle, and susceptible to explosive breakage.
High EMC makes wood take set quickly. Wood becomes less likely to break, but takes set sooner.