I guess my question is-
Does a chain anchor hold better than a pyramid of the same weight?

Also Todd-
Understand your concern about dragging. We have been using the inner tub full of gravel(round ball) for 25 years on the Skagit and also make sure it is out just far enough to bounce along to keep the nose of the sled straight. Do not want it dragging along at all like you said. We use it almost exclusively for Coho fishing as we drift and throw Dick Nites or jigs.