Mark, the sculptures did warp while drying, but I sanded the bottoms before bisquing until everything was perfect. Then they came out of the kiln a mess! I found that you're right about cone 5 -- it is a pain to sand, although I had some successes.
Thanks MMB for the mention of the Diamond blades. I purchased my angle grinder from Harbor Freight - a favorite fun store where I find all kinds of great things for the studio.
Big Lou, it's possible that I'm not drying the work slowly enough. I do dry them on a rack and I candle them for a long time (8-12 hours) before using the slow bisque setting on my kiln, and I frequently use sand. I'll try compressing better the clay slabs that I use for bottoms.
And I don't know what "plucking" is!!