The latest hive theory didn't work

From the last post, instead of 1 orchard grass, we did dinner as 2 alfalfa and 1 local.
Didn't work.
The hives are an unusual pattern (mostly hive-free on his side (ribs) and only small ones on his butt and belly, but his neck is pretty hivey), but I was hoping for the miracle from a week ago where they were almost completely gone for two days.
If they're still bad Saturday, I'm going to switch him to:
am: 1 alfalfa
lunch: 1 orchard
pm: 2 alfalfa, 1 orchard

And see if it is the local (doubt it).

I also ordered Equi-Derm from Riva's Remedies, which I had forgotten we tried last time; I gave him an extra wormer tonight (Ivermectin; he got Anthelicide EQ last week when the farrier was out); and I ordered him some Strongid feed through wormer in case somehow this is coming from worms.

I also emailed Dr. Mansmann at NCSU, who got his PhD in horse allergies, and he asked some questions and I passed along Dr. Mike's contact information.
Beyond that? I have nothing.

Also, tonight I couldn't ride because of the wither hives, so Willig got lunged and it was either the cold or the alfalfa or the combination, but he got the crazies a couple of times. He's in his space suit blanket for this week, with nights below 30 and the days barely above 40.

More about the hives

Willig's hay until Friday the 26th:
am: 1 alfalfa
lunch: 1 local
pm: 3 orchard grass
This variation, we know, causes hives with the "winter" purchase (maybe the 1st cutting from the year??).

Willig's hay on Friday and Saturday:
am: same
lunch: same
pm: 1 alfalfa and 2 orchard grass
This variation made the hives noticeably decrease by Saturday afternoon. (So Friday night's meal alone made a huge difference.)

Willig's hay on Sunday, Monday, and Tuesday:
am: same
lunch: same
pm: 1 alfalfa and 2 timothy
This variation made him break out in fresh hives. Yesterday (Monday) there were some huge ones, and a lot of new ones. Today there were a lot more, but not as many huge ones.

So I am going to try for the rest of the week (Wed, Thurs, Fri):
am: same
lunch: same
pm: 2 alfalfa and 1 orchard grass
And cross my fingers that this combination, combined with the Platinum, can keep him hive free until the barn works through the big load.

What I don't get is that the timothy works for the other horse with exactly the same problem (she clears up within 2 days), and the feed store thought that horses with allergies were more allergic to alfalfa and less allergic to timothy because it has fewer minerals in it.
Willig seems to be more allergic to timothy, then orchard, then alfalfa.

The poor guy seemed a little depressed today, and itchy too. He kept his tail in the air a lot, which isn't like him either. I also suspect it's making him "itchy" on the inside, because he seems to get smegma faster, like maybe it's like the people who are allergic to wheat and their intestines act up? (His poop looks fine.)
Have I mentioned I'm frustrated? Why isn't there anything about this on the internet?