I just had to respond to this thread! I hate to admit to this, but I'm large, too, though trying to "shrink" right now! I tried on almost every single BC made for women, and NOTHING fit me right. Tried on most of the men's BCs (I seriously went to every shop within 100 miles in any direction of my house, and drove MUCH farther to OceanFest to see what I found there, and made a point of finding exactly which shops carried BCs that I hadn't tried yet!). I'm short (5'3" or so), and by the time I got a BC (men's or women's) that fit around me properly, it was either FAR too bulky to be useful, or the shoulders were so big that I could put baseballs between my shoulders and the straps! It was terrible. During my open water class, I used rental equipment (men's, of course), and floating on the surface was a real trip! I had the shoulder straps somewhere around the top of my ears! Admittedly very funny to see, but not so amusing to actually wear.
The other major problem I had with fit was my chest area (which was part of the problem with needing a larger BC size than expected). Every chest strap was uncomfortable, and because of the size of the shoulders, I HAD to have it attached/strapped down, or the shoulders would just fall off me. I have a large chest (built in buoyancy! Haha!!), and the straps were inevitably in a terrible position. . . I was smashed down, squashed UP or cut in half. Very bad. And terribly uncomfortable. I was to the point of giving up and just taking the cheapest BC I could find (after all, I couldn't see paying a lot of money for something that wasn't going to fit me well, anyway!), until I finally tried on a Zeagle Zena. I was in love with it from the moment I tried it on. The shop switched out the shoulder section to a size smaller than the body section, and I got a PERFECT fit! They put me in the pool with all the equipment, and I happy bubbled from one end to the other and back, over and over again. I tried all the buoyancy "tricks" that I never could accomplish when using the rental gear, and had no trouble with any of them. I was overjoyed! Because of the adjustability of the Zena, your shop can switch out different sizes on the individual "parts" and get a perfect (or at least very close to perfect!) fit for you. As I lose weight, I will be able to switch out the pieces, and not be required to buy an entirely new BC. And, best of all, the front zips up like a bathing suit, no straps across my chest, so I don't even feel it once it's on! It's the ultimate in comfortable. I can't even begin to tell you how much I love that BC! My only complaints are that I would like more D-rings (easily fixed), and it would've been a great idea to actually give this BC pockets! There's only one pocket, a removable net pocket that folds out or tucks away when not in use. I truly don't know that I will miss the pockets if I get more D-rings (camera, safety sausage, flashlights, and I'm pretty much out of rings!), but I do kind of wish I had more than just a long, expandable pocket. I don't want to put anything in the pocket because I'm aware of how far down it hangs when expanded out.
Good luck! The BP/wing idea would probably be just as useful, but I think you should do yourself a favor and at least give the Zeagle Zena a try. I had given up hope on comfort until the shop put me in that BC and changed out the sizes on the shoulder section for me. Sorry for the long post, but this is really a subject near and dear to my heart, or at least various other parts of my anatomy!
Dana