I require deep concealment and can't reliably wear a jacket to cover up a shoulder rig, so I have been experimenting.
I got a cheap belly band just to see how it was. I didn't put a lot of hope in it, just made a tiny investment. It's not terrible, in a way, but in another way there's no way I could trust it. If it had an additional strap to go over the shoulder it wouldn't hurt, but I still don't think I could feel as secure as with a good IWB.
I also went back to Mexican style carrying for a while, which I do crossdraw on my weak side. It's not good for drawing, granted, but it's secure (I have a quality gunbelt) and I can bend over to reach for things without the butt printing through my clothing.
And now I'm experimenting with my strongside IWB on my weak side, crossdraw. Again, drawing is not ideal, but the additional retention of the holster (over Mexican style) is nice, and again, I can bend down to reach for things without fear of the butt printing.
And I'm now considering using my weakside IWB (mirror image of my strongside IWB) on my strong side, because the draw, if the holster is back enough, is not bad. Instead of reaching with palm facing my body, my palm would face out, but I could grab the gun with a firing position and remove it from the holster with little more obstruction than drawing strong side from my strongside holster. It just requires a little twist once it's free of the holster, and I'm ready to go.
Hopefully I'll have an update soon.