I am not mocking. We all have to start from scratch at some point, and we do not know what we do not know, until we know a bit more.
After 45+ years at the bench I am still learning.
What I was trying to say, and I may not have said it well, is that a correct fit of a genstone ( this is general, not always how it goes), when you set a gemstone on top of a setting that is correct for it, it should be larger than the inside circumference of the space between those prongs, sitting on top, and you should still see roughly 50 to 60 % of the prongs exposed. Roughly I said.
You can often adjust those prongs in or out some to this fit.
You next take burr(s), and “carve” a “seat” that perfectly fits your stone, leaving enough prong metal to “close” your setting over the gemstone.
Some of this is just Art, and you get there through trail and error.
As one apprentice I had was taught at a GIA class he took, you " burr a little, look a lot".
That describes good stone setting.
It is not a science, but an art.