Materias and stat value

Hi,

I've been wondering, planning to meld some materias onto my gear, how much a VIT4 (+8) corresponds to in terms of HPs ? Is there a matching table somewhere ?

Also, I'm wondering if there could possibly some other criterias, such as the race of your character, or whether it is job-specific ? (as in Vit4 would grant a tank +100hp, whereas it would give a summoner only 50?)

Is the number of HPs received linear (as in, Vit I = 1pt = 50hp / Vit IV = 8pts = 400hp)
Or is it exponential after some point ?

Any input would be greatly appreciated... If you know a of a link about the matches and weighs for each different materias, that would be really awesome.

Thanks

1 point of VIT is equal to 14.5 HP. Class/Job makes no difference.