Usually 2-3. He said he can't hold the concentration needed to make those shots with more arrows than that. But he said he has his range right behind his shop, and goes out and fires off arrows thru the day.
Yup, that what he does. Said the same thing to me. Can't concentrate on shooting more then 3 at a time (I think it's in his book also). Then takes a small break to get the arrows and regroup.