Furqan Shafi

Going away from Ex can be tricky. There are many types of VGs. Many of them of not very desirable with girdles quite thick, crown too steep, pavillion too shallow/deep. Nicers VGs don't trade at a much discount compared to their Ex counterparts.

More than VG, i think you won't be able to tell G from H apart. So that's another direction you can look at.

Certificate "Choice # 1" would be my choice.

It would be very difficult if not impossible to find a dark diamond (due to the cut) among GIA excellents. So you're good. Other than that if you can spend half the time looking at diamonds rather than reading on internet you will be able to decide for your self if you are prepared or not to pay a premium for the Tolkowsky proportions.

Yes by size I mean the size category. I say this because instead of 0.90 E Vvs2 you might be able to get a full carat G Vs2. And it would generally have no legible difference, given other things remain same. You can use the diamond finder on this website and see what you can get for your budget so you know exactly what you can expect within your budget. You may also be able to see videos of the diamonds which tell you much more about the stone than just a certificate. About the certificate - there's nothing on that certificate that can tell you how will that diamond look. It only tells you depth and it tells you table size. See it says profile not to actual proportions. That diagram represents nothing. The fact that it says the stone have Excellent polish and Very Good symmetry means nothing much except that according to GIA it has excellent polish and VG symmetry. Even a glass type shallow diamond can have excellent polish and excellent symmetry.

I think you should search for diamonds based on price first then on color clarity. Here's a small tip on searching Search for D-G color, IF - VS2 clarity, None - Medium fluorescence. Sort them by price lower to highest. And start finding diamonds in that order in different carat categories. And see what you get in your budget. It's wiser to maximize size first within reasonable color clarity range. Try again.

Under such level of magnification almost every pear and oval will show some level of bow tie effect. How that translates into real life is totally different. Some excellent symmetry diamonds may have bow tie effects as well. The symmetry relates to how well aligned are the facets to their corresponding facets. It doesn't take into consideration the crown and pavillion angles of which a product is your bow tie.

It does affect clarity grade in my experience especially when stones are on the upper spectrum of clarity. What you are saying near the culet is unlikely to be a clarity characteristic but more along the lines of some reflection artefact.

Clarity grade is not based on light return. It's based on what's visible to the diamond grader under 10x magnification. So yes it may or may not have an impact on the clarity grade but that will be independent of light return. Also GIA does not grade any diamond for light return and nor does HRD or IGI (the other 2 most popular labs globally). HRD sometimes however does leave a transparency comment but that's not the light return you're talking about.

Which by the way they would have to be to achieve that crown angle at that girdle thickness.

If I am really splitting hairs I would say the table sizes are a tad bit small.

The cut is fine. These parameters won't give you nail head effect. I wouldn't change a thing as far as the cut is concerned.

Absolutely

There does seem to be a bowtie. If that's a good or a bad thing is open for debate. More than the bowtie itself I would ask the question if you like how the diamond looks out in the sun since I can see this diamond shows a fair bit of fluorescence?

It is indeed a busy diamond for a SI1. Difficult to tell impact on brilliance from certificate or pictures.