score:2
I'm not an expert on Roman military tactics, so I don't know how accurate this is, and they don't mention or link any specific scholarly sources, but I found a youtube video from an educational account about this. Hopefully someone who knows about this stuff can comment on its reliability, but they have rather a lot of historical videos of this kind of stuff, so I sure hope its not all nonsense. Either way, you can compare its visual presentation to what Gibbon reported.
https://www.youtube.com/watch?v=Ndh3b9wC-A0
It uses a lot of footage from Spartacus, like Santiago suggested in the comments, as well as some footage from the recent HBO series Rome from 2005. The basic gist seems to be that they marched to battle in a huge checkerboard pattern (quincunx), then each maniple would deploy into a line (triplex acies) that appeared from the vid to be 8 men deep. Front ranks would move to the back to rest after a little while, so each position in the line operated like a conveyor belt keeping the freshest men on the front.
Here's another video I found going into detail about how the "maniple swap" was accomplished. Dude says he's researching this for a graphic novel he's working on. He's critical of a lot of what's in those two videos, so its probably good to listen to afterwards as a caveat to that other video's presentations.