i think it kind of depends on the freezer and how much meat you are stuffing in it. we have one freezer that in 2 hours it would be completely frozen, and other one that 2 hours would be just getting stiffened up nicely. I dont know about everybody else, but I cube mine up into about 1.5 to 2" chunks and then lay it out in a single layer on metal cookie sheets and then into the freezers, I find that the side touching the cookie sheet freezes pretty fast so after a half hour to to 45 minutes on average I will take a spatula and flips the chunks over and this seems to speed the process and make for a more even freeze.
If we are quick enough we can usually get it through twice before I want it back in the freezers, but if not I will chill again between grinds or if I am going to run it through a smaller grind on the second pass it always works better for me if the first grind is froze/near froze and it flies right through with little effort.