p.1 #2 · Can anyone explain the difference to me between these 2 grids
To some degree (pun intended) you can see the difference in the photos of the grid themselves. Light spread outward from the softbox will be just like it is facing inward in the photos. Think of each individual element in the grid as a light shaper. A hexagon is more circular so will be more focused with less spread compared to a square which would let more light escape the corners. Assuming the individual cells in each grid are roughly the same width, the squares would allow more spread.
The degrees of light spread correlate to the area of each grid cell. Smaller cells = narrower spread. A hexagon has a smaller area than a square of the same width so you'd expect less beam spread.
The depth of the grid is a factor too. It's difficult to tell that from the photos although they look similar.
p.1 #3 · Can anyone explain the difference to me between these 2 grids
It would appear that the egg crate grid has more cells and that typically means less light spread. It’s unfortunate the manufacturer didn’t put the light spread angle on the egg crate specifications. You can obviously control the light spread by moving the octa closer or further away or feathering it a bit on the subject. Given no other information, (personally) I would probably prefer the hex version.
p.1 #4 · Can anyone explain the difference to me between these 2 grids
Thanks everyone who chimed in.
I found an old reddit thread thread of some people discussing this exact thing, and the consensus there was, with only the shape of the cells being different, and everything else being the same, almost nobody would notice any difference between the two.