ToME: the Tales of Maj'Eyal

If I get the "Stone Alchemy" talent line from an escort quest, its skills will max out at 4.0 (0.8 x 5) I know that some talents use the base level (i.e. how many points you have in it) and other talents use the scaled values (i.e. some classes have it better than others)

Does anyone know which way Stone Alchemy works? Will my paladin have the use of all gems, or is she going to be restricted to tier 4 gems? Is she going to have access to the prodigy that gives you the ability to enchant helmets and belts?

In the stone-alchemy tree, extract-gem and imbue-item both scale with the raw talent level and will allow you to work on tier 5 gems when maxed. Only the distance of gem-portal and duration of stone-touch use the effective level.
And you will be able to get the crafty hand prodigy is imbue-item is maxed.