https://www.reddit.com/r/ffxiv/comme..._and_percents/

I tried asking on reddit; I don't know if this is an ok thing to ask since SE doesn't like talk of DPS or whatever, but the property stats like Critical, Speed, Determination, and Accuracy seem arbitrary if I don't know exactly how they affect my character.
"Determination 600" Wow that's... cool? Is there any data out there that can describe what the in-game values mean on a percent basis? How do you know if you have enough accuracy for raid bosses, how does speed affect HoT's/DoT's now, etc.