Whiteflash has 3 tiers of stones. Their top of the range ACA, followed by Expert selection(ES) and lastly Premium select (PS).
Usually the ES are those that just miss the ACA mark. It is often hard to tell the ACA apart from the ES. Often people who buy online get the ACA but pple who actually go into the Whiteflash store sometimes end up buying the ES as they can’t tell them apart.
But dropping to the PS can be said to be noticeable. Look at the 2 scopes. The lighter red is weaker light return. The problem with reading aset is that Whiteflash use a black background so it’s not so obvious but u can clearly see it in the idealscope.
Here are another 2 stones u can consider. If u really want to maximise budget u should consider SI1 clarity. These are vetted in house by Whiteflash to be eyeclean as opposed to dropshippers where u dun really know.
Note: 0.6c is not a flat caret weight. The flat weights are 0.5 and 0.7C.
These 2 options are also priced lower than your choice
0.603 G SI1 (expert selection)
https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3999718.htm
0.56 F VS2 (ACA)
https://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3824331.htm