As I promised, here's the sorrel jam "recipe". Since I made this after making jelly, there was an awkward messy stage where I was plucking the seeds pods of the sorrel out of the goopy seedy petally glop that I had in the jelly bag. There was still enough liquid in there that I didn't feel like I need much more, but I did end up rinsing some of the seeds, poured the liquid through a large-hole sieve, and probably added about 1 cup more water that way. (If you just wanted to make jam without the previous jelly step, I would suggest just breaking the petal off the seeds while fresh and cooking them with a 1 cup of water per pound of petals til they were falling apart and mushy, probably about 15 minutes, more or less).
Once I had just petals, I added sugar to taste (a lot). I'd say about 1/2 cup per cup of sorrel, but I didn't measure. I just stirred it in until it tasted pretty sweet, but with a tiny bit of tart.
Then I boiled away, stirring often, for about 10 minutes. I didn't wait for it to jell or anything, since it was already so thick and since I'd just seen what the jelly did, I wasn't concerned with its performance. It did not end up being super jelled, but it is a nice spreadable thickness...
Process the jars the same way I did with the jelly. From the original 5 pounds, the jam made an additional 6 half pints, but I would guess, maybe, you would get a higher yield if skipped the jelly step?