ptpeter - I think there are several advantages to conicals, but definitely among them are the freedom to dump the solid bottoms to potentially remove yeast that may have died or become inactive, as well as to remove other solids that float to the bottom. This holds in the case of most ales, which typically flocculate at the top. In the case of lagers, which floc at the bottom, you could dump active yeast. I would think that after 1-2 weeks you could dump the bottoms and then continue to "2ndary" in the same conical, if desired.