Barry--I have seen many I's that face up very white...but have not seen a J that doesn't show a hint of yellow..some more than a hint. I'm sure you know your diamonds much better than I, but my advice for someone who is buying online who will probably not see the stone before purchase is to stay safely out of the J range, esp if you are on a deadline or timeline for the item to be set and completed as there will not be time for the return of the stone to look for another. If you are buying in a B&M or similar and can see the stone before purchase, many may feel comfortable with the J if it faces up white. But for me personally, buying online I would not go over an H..even I's can be tricky unless you see them in person. My two cents though...
Swan--If you want to go slightly under 2.0 there will not be a noticeable difference between say 1.85c-2.0 most likely...under that you may get a bit of a visual difference, but if that concerns you, pay attn to the diameter of the stones you are looking at. See what a well cut 2c stone will have for a diameter and then imagine what a difference in tenths of a millimeter will look like. Chances are if the stone has a superb cut then it will make the stone look even bigger and brighter than it really is. Lugus just bought a 1.78c when he was looking for a 2c originally. In the end he got an AMAZING looking stone for his budget, can't wait to hear what it looks like!!
Riley--I'm definitely not an expert on the light return concept, maybe Rhino could tell you more, but I believe that image is taken through an IdealScope or Rhino's version of one (I think he is coming up with his own version of a light return viewer). For many H&A's the arrows *can* definitely be seen when viewing in regular light, through sunlight, diffused light etc--if they look crisp and defined on the light return image, then they should be visible in certain lighting circumstances and definitely under a loupe!
Perhaps others can weigh in, esp those with H&A stones or Eightstars?