You can also ask online jewelers to show you different photos of real ring on different finger sizes, such as this:
Do note that the article has sizes in US. Convert accordingly to get a grasp of the approximate size for local jeweler. MY should mainly be HK size.
This is only true if the 0.4ct is terribly cut, but this may only happen if you are comparing at the 2 sides of the extremes. In real life, if a jeweler offer you an excellent cut 0.4ct, it will 99% be bigger than a 0.3ct. I don't think any jeweler will pick an extremely bad cut diamond to sell to you.
Any tips on shortlisting the "worse inclusions"/"prominent areas" that have them to filter?
I am no expert, so I will just refer to this: https://niceice.com/diamond-clarity-grades/
In real life, just try your best to find a diamond that is not milky and don't have any black inclusions on the table. Transparent inclusions are usually much more preferred. As for "inclusions to avoid" stated in the article in the link above, if the diamond has a good clarity, let's say VS1, to me it is still acceptable, as simple as that.
Also noticed I couldnt not get the free daily 3 times HCA calculator to view, is it still available fore x3 free daily?
Try to use another browser or use incognito/private browsing. I believe the website has some cache that is stubborn enough not to give you 3 times per day.
have some shortlisted below, would you pick any these over your earlier choices?
I can only answer you for diamonds around the same carat weight range, which is the 0.3x ct range. For 0.3x ct range, I will still pick the E VS1. I like the colour and clarity. I won't pay more for a higher clarity but lower color, and I don't feel like stretching to a G color the little bit of extra size.
As for 0.4ct, this is a whole new tier. Price difference is there. If my initial budget is at 0.3x ct, I won't bother looking at 0.4ct, so only you can answer whether you willing to upgrade your budget. If you are willing to do so, then I will pick higher carat weight over smaller carat weight.