I was recently looking at the Regeneration spell (Creation 10), and wondering how I could achieve Regeneration 20 with it. This would seem to require a spellcasting attribute score greater than 20, which is as far as I know, not something you can point-buy up to.
Assuming that all of core (including Game Master's Toolkit), the Prometheum; Dominus; and Arcana Exxets, and additionally Gaia: Beyond The Dreams are available how else can one raise one's spellcasting stat? Answers may assume that any attribute that can be a spellcasting attribute, is a spellcasting attribute.
We are using the variant rules where one can spend level-up points on advantages.
To be clear - the question I am asking is "how can I boost my spellcasting attribute higher than 20", and not "how can I get Regeneration 20".