How is fiberboard in comparison to plywood for making boxes? (comparison pic found online)

Is a 5/8" vs. 3/4" box going to make any real difference to an audio beginner? I've got more 5/8 then 3/4, but I might be able to make the box out of 3/4" if it makes a reasonable sound difference.

And a third question, I have two Pyle 500W 4 ohm Blue Label subs that I trash picked because they are like new, some of you might remember me because of them and I'm getting ready to make a box, just for one, for now anyways, just to play around with. No manufacturer recommendations found anywhere even on the internet because it's not supposed to come out of pyle's bandpass box (trashpicked bandpass box was screwed, trust me). I was going to do 12" square OD but any size recommendations are welcome. Thanks in advance.