You are going all out on anchor
gear here. 400ft of 3/8th and 100lb anchor! That seems like a lot for that
windlass.
If the spade is a 160, then its 77lbs. A decently large anchor for your
boat. You could get it re-galvanized.
Maxwell states "The maximum pulling capacity of the
windlass should not be less than three times the total weight of the ground tackle." Seems like your setup would be on the edge of that.