What's the best GURPS thaumatology system for a minor godlike boss being?

[SolemnGolem]

Originally Posted by AlexanderHowl

It is double the level of the highest Realm required for the effect plus the sum of the other Realms.

Good to know, so if the spell only requires a level 1 in that realm, then it can be capped at 2 x 1, even if the caster knows up to level 4. (Otherwise if you had to multiply by caster's highest known level, you're basically increasing the cost of all spells just because he knows more levels...)

Regarding Realm vs. Verb/Noun, what are the benefits or drawbacks?