Just had another opportunity to test. Had a 30/40% lie in sand on a 16yd hole. Used my CG64 wedge to flop (19yd range) and used 100% power. That shot should have gotten fairly close to the hole but it actually didn't make it out of the bunker, just moving a couple of yards...
4th hole at Kaiwah if that makes any difference, although it shouldn't...
Update: Decided to do some practice and take some bunker shots over and over again. I came to the conclusion that flops only work in 20% or less lie. I was never able to successfully launch a flop from 30/40% lie.
Maybe my memory is not serving me well but I am still pretty sure that I was able to flop from 30/40 not too long ago. I couldn't even find a bunker on Kaiwah or Merion that had a 20% lie. I'll try some more experiments when I find one.