So, here is the 4mm for comparison. I don't like it. I think it is too small.
Wow thats so strange, because I tried this one and it looked perfect with my motifs and it didn't look that small. Even the Tiffany SA told me to stick with that size versus the size bigger, even though it meant that I would spend less money. But I could see why you wouldn't like the smaller size. How curious. Next time I am at Tiffanys I will take a picture.