Is it better to have more scope with a lighter chain or a bit less scope with a heavier chain? Obviously it is the anchor that keeps you in place, but it is it not the scope and weight of the chain that keeps the anchor in place?

The idea of going lighter and longer on the chain sounds good to me; west coast anchorages tend to be in deep water, so I'd like to carry a longer rode. Longer and stronger makes a lot of sense.

5:1 in 60 feet of water means 300 feet of rode. If 100 feet were chain, I would feel very very secure in a more "normal" 20 foot deep anchorage with 5:1. (of course the flip side is will all that fit into my somewhat smallish anchor locker.)