Specific IV = Nature?

[Kinkedo56]

heres a question i've been trying to find out for some time now....from what i've seen not all shiny natures can have all 31 IV's right? and the IV/PID generator is supposed to tell u the IV's if u told them the PID and the other way around if u gave them the IV's. But is there like a list or some way to find out just how much IV's a pokemon needs while being shiny so i can actually use the IV/PID generator successfully without guess and test? and im also aware that different TID/SID affects it but what i want to know is how to find the highest amount of IV's while maintaining shiny with a random TID/SID that supports it for a specific nature?