Novus weapon upgrade system findings

[Nekodar]

You're also assuming that Alexandrite use is based on per Materia and not per Stat on the Materia i.e. it could be that you need 4 Alexandrite for a materia that has DET +4 and 10 Alexandrite for a materia that has DET +10. Speculation at this point regardless since we don't know the exact details.

Which is a reasonable assumption.
One catalyst - One materia...