Playing a shiny new hybrid caster (Astrologer) and I'm wondering how to use table T-4.6 (on page 47 of RMFRP, the Spell Casting Modifications table).
I presume if I cast an open or closed Mentalism spell, I shall use the modifiers on the Mentalism column. If I cast an open or closed Channeling spell, I shall use the modifiers on the Channeling column. But what if I cast one of my base spells?
Do I average each modifier? Take the worst of both? The best of both? Are there guidelines I've missed, and if not, what do other people do?