This might have been mentioned, but I basically just skimmed the page.
One thing I noticed, that relates to this topic, is that weather seems to trump the day for geode and -ite drops. So even if you go out on Firesday to kill 'Monster X', if it's dusty weather, you're going to get earth geodes.

I'm not basing that on anything other than observation, so I know it's a weak point. But if my observation is true, then it's another thing to deal with. Quick answer would be go to abyssea, cause there's no weather, but then the monsters are generally too high and drop more -ite's than geodes.

I was lucky when I was doing my trials, I had just always lotted geodes and squirreled them away, and by the time I needed them they were only 30k ea. and I only needed to supplement my trial with a handful. I'd liek to screw around with another Str weapon or two, but it's extremely cost prohibitive.

In short, I do agree, there needs to be a way to up the supply of Fire Geodes in some way.

Craft Crystals to Geodes, or -ites to Geodes, or just a much higher drop rate for that particular geode based on the frequency(lack thereof) of the weather.