I'm so old I remember when a bag of sugar was 5 lb.
But I digress. Last winter's MC worked out just fine. I applied it on a relatively warm day in January to all hives. 2 of 5 barely touched it, but it was mostly hardened by spring, so was easy to remove. I figure their populations were big enough to moisturize the sugar. The other 2 hives ate most of the sugar. these 2 were smaller to start with, and were the ones I projected would use it. The 5th hive died anyway, and the loose sugar wasn't such a big deal to remove..
I think it worked the way it was supposed to.