Everquest's Internal dice mechanic - anyone know?

[TheRusty]

So for a long time I've been working on a project; I want to homebrew up a TTRPG version of EverQuest for my friends. While I know of the D20 TTRPG from 2001, I really feel it's Everquest in name only (and even then only barely)

While I think I can get most of the design done, I have one hurdle; I want the dice system to be as close to "authentic" as possible, but I have no idea how that would actually work.

First hurdle is just, what kind of dice system would it even use? My first thought is simply a percentage / D100 based system, since that has the advantage of being easy and seems to tie in with the /roll command in-game (I would guess that command uses a number string "randomizer" running in the background for all actions in the game, but, idk for certain)

But this is kinda tripped up by the stats themselves; How do you figure 255 Strength, 250 Blacksmithing into a percentile-based system, for example? Does it operate on thresholds, where every three points (or whatever) adds +1 to the potential outcome? It seems a little odd to have numbers like this if that's how it works.

So I guess the question is, does anyone have insights or understanding on how 1999 Era Everquest works "behind the scenes," how it determines outcomes of actions?