I think it's a few things. I think the thin band didn't flatter my somewhat larger and thicker fingers. I also think your eye gets pulled up towards the stone with the graduation.plua I think the increase in number of prongs helped. But I agree you often hear a taper in towards the diamond or a thin band all around make the diamond look larger. I don't have an answer for that for sure- I guess.
Reasonable guesses, Niel. I was only thinking that more prongs help it look larger. Most would agree that a bezel helps a stone look larger and so more prongs (rounded, not clawed) would have closer to the bezel effect, making the diamond seem larger. More photos please!