The tiller wont really matter much. I've been shooting three under for about 17 yrs now with about two dozen bows. The five I have and shoot now,none are tillered for three under. Had two bows tillered three under,a Palmer and a Wes Wallace, didnt notice any difference. All nock points about the same on the string and all were a little quieter split finger. I really think that actual DB for both ways are close to the same but three under is a little higher/sharper. Usually with a tuned bow you barely hear either one 15 ft away.