Additionally you could make geodes guaranteed drops from hybrid elementals in abyssea, regardless of the day. Baelfyr will always drop 1-2 light geodes and 1-2 fire geodes, for example.
-Edit- Or how about this: If you kill the hybrid elemental with one of the elements it consists of, all the geode drop slots will change to the element you killed them with, for a total of up to 4 of the same geode.
But seriously, this isn't anywhere near as good a solution as just upping fire weather in Ifrit's Cauldron and Lebros Cavern by something like 20-30 percentage points.
