Speaking from MY experience.... 90% I cut with BB.... 1/8 is comfortable with stacking ....4.... Five works, but that bottom one tends to have lots of tear out here and there. 1/4 BB I am still very Good with only 2. Three will work, but that thick to me is pushing the blade. Will dull faster. Safe than Sorry I say. Everyone has their own proven ways, but this is mine. Danny :+}