So along with the option of canting the sole of the boot, I thought it would be worth trying canting my forefoot. I cut some neoprene to match the shape of the boot board and then cut away the part that I didn't want to lift.
Today I tried skiing with my own cant, then again with more of it cut away, and with the Starthaus's recommended cants, and with the cants put on the opposite way at their suggestion. My cant felt kinda weird, and when I took it out I felt like I actually got less shin bang and a little better support up the whole medial side of the boot. Not sure why, but since these were my goals in putting in the cant, obviously it was counter-productive.
After that, I put duct tape temporary cants on my bindings and did some groomers with them oriented as suggested by the Starthaus's alignment check, and the opposite way. When I got off the lift the first time, I almost fell over my outside edge. That led me to expect that I'd feel a huge difference between having the cants on the right way and having them on wrong. In switching back and forth between having them oriented "right" and having them oriented the opposite way, I noticed that if I canted the insides of the boots, my uphill ski felt like it was just along for the ride - it got very little edge grip. The skis also felt kind of weird on the flats, and I sometimes caught my inside edge and got pretty pronounced speed wobble. With the cants on the correct way, I felt like my uphill edge worked slightly better, although not significantly so, and I was a little more stable on the flats - didn't get any speed wobble. However, when I took the cants away entirely, I didn't find that I missed them particularly. I got a little speed wobble on the flats, as I have been since I bought my setup, but my turns didn't feel much worse at all. Without the cants, my skiing is slightly less two-footed, but it wasn't a significant difference. Neither canting option eliminated my shin bang, though.
There are two options left for trying to get ride of shin bang. I can cut away some of the tongue shim Sako installed in my boots to help get the cuff tighter. I still have a couple of notches on the buckle before I run out, and the wings of the cuff have a ways to go before the touch each other after his liner trimming, so I think this is a good option.
My other choice is to try to find the cuff angle that works best for my ankle, mark where that puts the pivot point on the cuff, and then drill a hole in the foot part of the boot and put the bolt from the dual pivot plate into a nut on the other side of that. I'm a little wary of this option because the hole would be permanent and I think that whatever I put on the other side might create a pressure point that would require cutting away some of the liner to alleviate. I'm afraid that the liner might not be thick enough to cut away enough to do this, and both drilling a hole and cutting the liner are irreversible.
While I could always glue the piece I cut out of Sako's tongue shim back in, cutting it out in the first place seems like it could be messy and difficult, and the whole thing has the potential to have a pretty skanky-looking result. Since there's no skiing tomorrow and Tuesday, I'm going to give my shins some time to calm down, and see how the boots ski unmodified on Wednesday. After all, I've been skiing pretty much every day since the shin bang first presented, and because the bruise is more tender now that it's there, I might not know if I solved the problem with cuff cant alone.