BadMuzza:
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.
http://www.wgt.com/replay.aspx?ID=7788fb73-3d70-46ca-9192-a2e50144fbf9
I set up for the above flop from KI 30/40 sand by setting spin dot so it was ~'half-submerged in sand. 10% choked down on CG 29 Flop so ~26 yd nominal. Severe downhill after landing so BIG roll out. Carry was only about 8 or 10 yds so I just made it to fringe.
Bottom line, you can flop from KI 30/40, but the carry distance is considerably shorter (by 10 - 15 yds) and roll out is longer than from grass rough, because any backspin is scrubbed off by sand contact. My experience is that KI 30/40 is tougher than typical CCC/OLY/BPB sand of same depth.