Even a 20 lb. Danforth is not an ideal choice for a primary anchor, since they generally don't do well in shifting winds or currents. Fluke type anchors also have a lot of trouble resetting once they pull out... and can kite along if the boat gets any speed dragging. Also, having anchors of all the same type is generally a waste of money IMHO. If a 20 lb. Danforth has a problem holding in a given anchorage, the chance that a lighter Danforth will be of any use is very doubtful.
I would recommend that you go out and get a decent size next generation anchor: like a Rocna, Spade, Buegel, Manson Supreme, or Bulwagga; or a Delta. Something about 30-35 lbs., rather than what you've got now, and use it as your primary anchor with 30' of 5/16" G4 high-test chain and 150-200' of 9/16" nylon. That will probably be sufficient to hold your boat even in a serious blow. Keep the 20 lb. Danforth as kedge or secondary anchor.
Get rid of the other anchors, the sentinels and the mushroom anchor. It is pretty well known that when you really need the holding power, a sentinel isn't going to really be contributing anything to the holding power of the anchor, since the rode will be taut, and the sentinel will just be chafing along it.
Just remember, if the guys at the marina are laughing at how big the anchor on your bow roller is... chances are you're finally getting one that is about the right size.
While we are on the subject of anchoring I have a question. I own an O'Day 302, Displacement is 7,200 lbs, the anchor is a Danforth style #20 with 16 ft of 3/8 chain and 200 ft 1/2 in 3 strand nylon rope. When I anchor I let out a 7:1 or 8:1 scope in calm waters, then add a sentinel of 20 lbs of lead to a depth of about 2 ft from the bottom. In ruff water or high wind a scope of 10:1 and the sentinel along with a #8 mushroom anchor. I do have a second danforth style slip ring anchor about 15 lbs with 14 ft of 5/16 in chain and 150 ft of 1/2 in rope which I have not used.
Am I anchoring ok for Long Island Sound and surrounding area? Or do I need to do better.