I recently tried to scale some jelly recipes down. It seemed entirely reasonable: if you make the quantity specified in the recipes, you end up with far more jelly than a modern dining audience is willing to eat, and it goes to waste. And while the trotters and hooves might be cheap, the volume of wine involved ensures that it's still a luxury dish.
What I discovered is that jelly doesn't scale down all that well: I tried three different recipes (all from Messissbugo), two of which didn't set, and the third of which tasted too vinegary to be edible, because volume-wise it ended up with more vinegar in proportion to the wine. Each recipe I tried using only one trotter/hoof for (pork or lamb). Two of the recipes I hadn't made before, these were the two that didn't set. I suspect they need more feet in there to drag out as much gelatin as possible, because both the recipes specified that the hooves/trotters only stay in the mix for an hour. I'm keen to try them again with the full quota of hooves/trotters - however, it's a bit of a circular problem, because it will definitely make more jelly than anyone could possibly eat, but I'm also concerned that maybe the jelly just won't set even with the larger recipe, in which case I've just wasted a whole lot more wine.... But, it would also be quite nice to be able to make and serve some alternative jelly recipes, since they're a relatively common thing in period menus. The next obvious occasion to try it when I know I'll be cooking for plenty of people is May Crown, but that's really not a good time to be playing with something new - so for that, I'll be sticking with the recipe I know works, and actually, given that we have more bookings than we thought, the amount of jelly that the recipe makes as-is will be about perfect for the number of diners.