Need help choosing a diamond

[chill1986]

Hello, this is my first time posting on here. I have been searching for a diamond ring for my girlfriend for about two weeks now. Ive gone to all of the big companies like Mappins and Peoples. Ive also visited a few small businesses for differing prices. One gentlemen has told me that I can shop around at any store in the Toronto area and he will match/beat their price.
I am looking for a cluster diamond ring similar to...
http://www.itshot.com/diamond-cluster-rings-14k-diamond-flower-ring-130ct-p-35844.aspx#prod_detail

I have questions about sizes and qualities. If I choose a .4 carat diamond for the main stone in the center, and then choose maybe .15 carat surround diamonds to represent the flower stems will the size difference between the main and side stones be too large? Also, is it worth choosing a VS1 with an F colourless stone as the main stone being a smaller diamond. I was thinking of choosing a round cut diamond. Does anyone have an opinions on what type of cut I should look for with the round stone to really bring out the sparkle?

Budget:4000 max

 

[chill1986]

Bump

 

[Vizsla Girl]

The ideal parameters for a round stone would be:

Total Depth: 59 - 61.8%
Table: 53-58%
Crown Angle: 34.3 - 34.9 degrees
Pavilion Angle: 40.6 - 40.9 degrees

I am not familiar with this style ring, do you know whether you can pick the center stone?

 

[chill1986]

The jeweler said they can create the ring after I look for something I like. This design that I linked is merely a possible style that she likes. Those specific cut angles would be hard for me to see even with a magnifying glass to my eye. Is there anyway to discern an angle imperfection. I really don't know how to look at them