Yes, I did, and I'm really pleased with it!
I have this local Hollis dealer who has a full 25-yard indoor pool, who let me take it for a demo dive. Took me about a half-hour to figure it out, and I spent a little more than 1/2 hour in the water - then I went back into the shop and said, "CHAARRRRGE-IT!" Then I went back to the pool for some more adjusting, tweaking and fiddling - and another half-hour blowing bubbles, turning and pivoting, swinging the tanks butt-forward and going through their diamond rings, clipping them off and then on again, and doing all the "stupid sidemount tricks" that came to mind. I did that second pool-session with 6 lbs of lead and 1000 PSI in my tanks, neutrally buoyant with the wing utterly empty ... proof enough!
The loop bungees were a major problem for me, too -- I ended up just looping the valves with the thin guide-line bungee that connects the loop to the shoulder-strap. Good enough for a demo, I figured, and I had bolt clips choker-looped on the tank valves for the weight-bearing connection. I'll mount longer loops before I take the rig on my next vacation.
My tank-rigging is simpler, too ... I had fixed up stage straps, and choker-straps to hold the bolt clips close to the tanks, to mount my tanks on the ring bungees. Don't need that any more, just one bolt-snap on a choker at the top of the tank and another on the cam-band 8 inches from the tank base.
I'm going to enjoy this rig. Maybe I ought to buy a couple of tanks and a 5-mil wetsuit so I can enjoy it near home.