UPDATE: at least in the short term, I can't tell that I made any kind of dent in the SHB load of this yard. They have lots. All nine colonies are strong, and are managing them with beetle jails, some along the top edges of the frames built up to the cover, some with igloo/dormitories on the solid bottom boards. The best colony (which I should put in quotes "best" because they build like mad, pack honey like mad, and start defending their nest at 10 feet) has a crew of forty-ish bees running a corral of SHB *outside* the rear entrance which they chewed through the insulation board cover.
So, just so I can say I gave it a college try, I might drop another $35 on a treatment in spring. BUT, I think that's just beeing silly.
There was an interview I heard with Morgan Roth (new PhD at Va Tech I think) who has done a ton of research on SHB. Her conclusions are that since SHB: can smell a honey bee colony, especially tuned into stress/alarm pheromone, from miles (3? iirc) away; can fly for miles to get there; enter the hive in adult stage; do most of their damage as adults, it makes most sense to control/limit the adult population. She placed emphasis on trapping the adults in the hive. As I said, I have not been super successful with that.
She didn't say, but I'm starting to think that keeping them out, with an entrance mod would be potentially effective. I've read about the "guardian" and I have one that is still in my tool box. Where, it is 0% effective guaranteed :)
Iddee/Wally taught me how to make quick-n-dirty robber screens with #8 mesh. I have this faint idea that if I used that fine aluminum window screen instead of #8, and installed a "robber screen" on all the hives all the time, I might keep them out, or at least most of them.