The wedge was designed to move the bottom of the tank out a few degrees (or move the plate in closer to your lower back, which ever way you want to think about it). It also serves as a way to affix the wing to the plate so the wing doesn’t move all around when you’re trying to set it up with a tank. The top hole actually doesn’t matter because the tank will just rest on the wing/plate and cam band down into place.
i would suggest the DGX wing. It’s actually an Oxycheq Mach V wing just possibly a little thinner (IDK for sure yet but I’m buying one soon) which to me is good because the Oxy’s are too thick IMO…and expensive. And I don’t like the owner either.
That Hollis wing from what I can see would probably work too. It has a set of holes that will line up to 9 1/2” centers it looks like. It would be the two inside holes.
You have to excuse my tardiness to get back into this thread. I’m still a bit loopy from getting up at 4:30 and urchin diving today.