The maximum wave possible is primarily determined by how long your tank is. Mine's 4 feet so I get a smaller wave, about 3/4" or so.
But I must say that I'm not sure I'd want a bigger wave as when you look very closely, you can actually see your tank slightly jiggle during each wave. Kind of unsettling when you have a glass tank and live in an upstairs condominium <g>. My tank's a new Lee-Mar, eurobraced with 1/2" glass, so hopefully it's really sturdy....hopefully.
Whether or not it's an eyesore will depend on how much good I feel it does my tank <g>. I have it on the same end of my tank as the Stream, so it hides the Stream when viewing the tank from the front, which is nice. I took my other Stream out from the other end of my tank so now I only have one, which has improved the apperance. Kind of a trade-off.
I honestly don't feel it looks ugly in the tank, as it's a pretty fascinating item. People who've never seen one will likely say "wow" when seeing it the first time.
I'll guess it probably won't look as big to you as it does in the video because my reaction was that it wasn't as big as I thought it'd be.