I have the same setup as Stuart - Freedom Plate + Hog 23 wing. My setup is almost identical, but I did swap out the corrugated hose on the wing for a shorter 13" one. I did mount the wing using the middle holes, and I removed the plastic tank stabilizer tubes on the wing via a small incision at the top using pliers and my utility knife with a new blade. It was very clean and easy. I'll keep the tubes in case I ever need them in the future.
I absolutely love the strap Stuart recommended. I ran it around the middle of the bracket crossbar like Stuart did and under the crossbar for the top screw to hold it in place. The small amount of additional material necessitated a longer stainless steel carriage bolt. I initially tried a 3/4" but that was too short. 7/8" would be perfect, but I could only find 1/4" increments, so I bought 2 x 1" and ground them down with a hand grinder using two nuts on each carriage bolt to mark the exposed length for grinding. 1" worked perfect for the bottom of the bracket, and I used stainless steel nylon locking nuts on both top and bottom carriage bolts. With the rubber tubing on the rails, my tank is clear of the nut on top and doesn't scrape.
Also, I absolutely love the DGX scubapro-style cam bands to which I added some Halcyon weight pockets, and in conjunction with the tank strap, it's a piece of cake to set up and swap tanks.
It'll be Monday or Tuesday evening before I get a chance to get in the pool with my new rig. I'll be diving with my Faber HP 100 to check out the setup. As of now, I am planning on diving without a crotch strap. The way the backplate conforms to my upper back and sits above my hips, the belt is above my navel and below my ribs, so I think, as was mentioned in a previous thread by Akimbo, that it may not be necessary. I hope this is the case. I do have one though that I'll configure and take with me if end up needing it.
Here are a couple of photos: