For a long campaign I've been running, I expanded upon Hexagram 2's Astrology rules written by Stefan Jones. The core concept is to apply the effects of "flux" more broadly than bound wizards. I took my setting's calendar and came up with an astrological system for it (based upon the concept of lunar mansions but made up by just going on time-lapse through a stargazing program). I then associated elements and spell "types" with each lunar mansion. Spells or magics that are associated with these elements or spell types are affected by the flux just as if they were being cast by a bound wizard, and I allow a free point of mana per turn (use it or lose it) for every 2 positive influences to cast or sustain such spells (though you may never rest while sustaining spells, so I haven't yet encountered a need to limit this to avoid week-long spells, I would apply a minimum of 1 fST/12 turns to sustain spells if it was an issue. For my own purposes I enjoy some 'strategic scale' magic becoming available through astrology). Likewise, negative fluxes will increase the price of associated spells.
It still takes some knowledge of astrology to "call out" an effect, so ''normal" magic still operates as in ITL. However, when an astrologer would predict a lunar mansion to affect a given spell (due to element or spell type), it does, even if they are not the one performing the casting, so long as they are witness to the spell - though of course they may not know or be correct about the net flux! We might suppose this operates in a way related to Illusions/Disbelief.
I present my version of this as an example, but if the concepts here are interesting they should be adaptable to a different campaign's calendar and astrology:
https://docs.google.com/document/d/1...it?usp=sharing