Jerry, take a look at the following URL:
http://www.blue-crab.org/trotline.htmIt contains most everything you need to know about trotlining, and then some. The section concerning snoods or trots points out one particular benefit of using dropper lines off of the main line; changing baits. Using a slip knot at the end of the dropper lline, which come off of the main line, enables you to quickly change/replace baits, with no wear and tear on the main line. The metal clips are also a good idea, but a bit on the pricey side.
Crabpop