Differences in oval facet patterns

[leukolenos]

Could anyone please explain the differences between the different oval facet patterns?

For some reason, the 4 and 6 mains seem more attractive to me, am I just liking the fewer/larger facets?
What are the pros/cons between the different facet structures?

I've also seen a few that look almost like cushions? What's up with that? Like this-


Would love for someone smarter than me to explain the technicalities, reasons for using different patterns, what to look for, etc. I've found lots of information explaining basically that there *are* differences, but not really explaining the how's and the why's.

 

[RockBrat]

I used to have an oval so i can provide some basic info that I've learned but hopefully others will chime in as ovals are uncomplicated yet very complicated, lol!
4 mains produce the largest flashes of fire,  8 mains produce the smallest, more pin point type flashes of fire. You probably like bolder, larger flashes which is why you lean towards 4 main or the 6 main which is a more balanced fire flash.
To get the best oval, you want to look for numbers/angles that are mostly within the range of excellent cut rounds. There are exceptions to this and the numbers will not line up exactly but they should all basically be within the range of what you'd get in an excellent round.
An oval that looks like a cushion contains hidden weight. So you will pay for larger carat weight but won't see much of a face up size difference other than that the oval might look taller from the side view. I actually like this type of oval but why pay for weight that you might not be able to see?
The smaller the length to width ratio the closer the oval will be to a round and the larger the ratio the closer it will be to a marquis (moval). 
Now for the complicated bow ties. The depth of the diamond, the mains, and the length to width ratio all play a factor in the size of the bow tie. Theoretically, a 4 main should produce a smaller bow tie and an 8 main should produce a larger bow tie. However, a bow tie tends to get larger at about the 1.5 length to width ratio. The depth of the diamond plays a decent role in the size of your bow tie as well but a 4 main should minimize the effect over an 8 main. Although, bow tie doesn't determine the performance of the diamond, it's just there. You could have a very small or very large bow tie in an excellent performer or vice versa.

 

[Rockdiamond]

Hi all,
Without a doubt many people want a simple answer when doing this kind of research.
Unfortunately with oval diamonds any simplistic answer will be incorrect for a nice percentage of stones.
Not ever 4 main or 6 main Oval Brilliant will have the same sort of light performance.
Difference in the crown, table depth and other factors mean two stones with the same diagram on the GIA report will behave differently.

Could anyone please explain the differences between the different oval facet patterns?

For some reason, the 4 and 6 mains seem more attractive to me, am I just liking the fewer/larger facets?
What are the pros/cons between the different facet structures?

I've also seen a few that look almost like cushions? What's up with that? Like this-


Would love for someone smarter than me to explain the technicalities, reasons for using different patterns, what to look for, etc. I've found lots of information explaining basically that there *are* differences, but not really explaining the how's and the why's.

That plot shows a stone that GIA would classify as "Oval Modified Brilliant"
Again, no simple answers here.
I can say that the thought that the cutter would only use this design is to hide weight is simply untrue.
There's cases of OMB's that are lower depth and have HUGE face up for the weight.
Of course in other cases an OMB can be a "steep deep" and face up tiny for the weight.
It's case by case with ovals......