Haven't been doing this long enough to have much actual experience. However, I did ask Brent Walston about a similar problem I was having, and he told me (paraphrasing) that he leaves sacrifices "until they've done their job (sufficient thickening) or until they start creating a problem (like reverse taper)". The best situation, as I understand it, is to have multiple sacrifices at different levels but that's not always possible. Interested to hear the experience of others on this.
Chris
