I believe the maker's mark reads ACME in Gothic script. This mark is different from the one commonly used by the Acme Silver Co of Toronto, so it may have been manufactured by another Acme. Hopefully, someone else will provide more information.
In my understanding, DWTS stands for pennyweight and was used by some silverplate manufacturers to indicate the amount of silver used in plating base metal.
One dwts is equal to 1.55 grams, so 24 dwts would equal 37.3 grams or just over one troy oz. Needless to say, a spoon over 12 inches long would surely weigh well over 3 troy oz (that is, more than 100 dwts).