I always found my Danforth to be an excellent anchor in the Delta except if the bottom is grassy. Then it will never hold. I had a depthfinder/fishfinder which gave me good indication of the bottom type. I just would not anchor in grass, even for a lunch break or a bit of fishing! If anchoring overnight, I always did a "Delta Tie Up" using my main Danforth off of the bow and my smaller "lunch hook" off of the stern. This allowed me to keep the O/D in 4 ft or move of depth, but have the bow up close to the bank which is needed on the narrow sloughs of the Delta. One one occasion my bow anchor dragged, but my stern anchor kept the boat from going down the slough with the current as I slept! I was rather surprised when I awoke the next morning!
I have never anchored in the bay, so I cannot speak to those conditions.