I took a head of garlic (peeled), a bunch of dried flaked ginger chips and some gin, ran it around in a food processor to make a coarse paste. I cut the strings tying the roasts together, put this stuff in the middle, and reassembled them.
I made up a big batch of pomegranate-molasses brine (with herbs, peppercorns and the rest of the gin). One of the roasts is in a big ziploc in this stuff, and will be cooked to a nice medium tomorrow night. Then it gets to rest down to room temperature and sit in the fridge until Saturday evening.
The other is wrapped in saran in the meat drawer (where it won't quite freeze), waiting for the same treatment in a little over a week (it's going to be much more strongly flavored by the garlic-ginger paste).