I am looking at Princess cut diamonds but it is very hard to find a diamond that falls in the range of 62-68% that seems to be recommended, so how does a larger table say 72% effect what the diamond looks like???
Man, looking at pear-shapes, princess cuts. Sounds like you haven't quite decided on what shape to get! Coming from somewhat of a diamond novice, I believe that GENERALLY (don't mean to yell but want to make clear this is a general statement!) you may get more brilliance from a larger table, but sacrifice dispersion (color flashes).
Also, from what I recall during my search for an emerald cut, you will find many princess cuts with tables larger than "ideal". Cutting a larger table has the "added" benefit of making a diamond appear larger than a diamond of similar size cut to "better" proportions.
If I'm wrong, I'll let the experts beat me up. Hope that helps some.