The Zena is modular, which means you can get a custom fit by mixing and matching the components. Call ScubaToys with your measurements and have them custom build one for you. Keep in mind that there's a proper fit that many don't know about or do properly. I'm also large on top and I love that the Zena doesn't add bulk to my chest area.
The middle strap should sit below your rib cage at or near your natural waist. It isn't uncommon for women to think the bottom strap is at the waist, but that is incorrect. The lower strap is almost at the hip level, and once the Zena is adjusted properly, it should never roll or move on your body. The shoulder straps are simply snugged down, not tightened as the corset effect of the Zena holds it in place.
The easiest and best place to get your Zena tightened properly when diving is IN the water. Once at about 10' deep, loosen all the straps, pull the BC down by the sides, and tighten the middle strap below your ribs/at your natural waist. Then you snug the bottom straps, take the rest of the slack out of the middle strap, and take the slack out of the shoulders. I find this easiest to do when horizontal in the water.
I've had my Zena for 12 years with nearly 700 dives, and other than some fading, you really can't see much wear. I did have a dump valve fail and it went back to Zeagle in January where they replaced the entire bladder and inflator hose for free, but after 650 dives, nobody can say that some kind of failure was unexpected.
I recommend any woman looking for a minimalist BC who doesn't want to go the BP/w route try the Zena to see what they think. No one BC or rig is for everyone, so it's good to try a lot of options before deciding.