Right now, what we've learned limits our reach to just the city and only to magical girls right in front of us.
I disagree with this assessment. Consider the amount of grief we've pulled out of various Meguca over the past few days even with massive amounts of combat, healing, and general power use. A thousand grief marbles and some change. Now consider the grief to blot out the sky and run basketballs of grief around in addition that cleansing a grief seed produced. We're probably talking about at least 1,000x, likely a couple magnitudes more, grief stored in a single grief seed than we've cleansed out of all the magical girls we've been treating so far.
It's quite plausible that a
single fully cleansed grief seed could last a meguca for
years. The grief density we observed in cleansing a grief seed is enormous. It's likely that the length a single grief seed could last a meguca is more dependent on the internal production of a cleansed grief seed, which is something we might want to investigate itself, the figurative shelf life if you will. Our preliminary experiments don't seem to indicate a significant production of grief from the seed though in that state compared to its total capacity. Even if it produces 100x the amount of grief that an active meguca does the grief seed would still last around a year.
Based on what we've seen so far though we could likely give each meguca a cleansed grief seed once a year and never see them otherwise and they could go about normal life the rest of the time. Taking a plane to Mitakihara once a year is not that big of an inconvenience. Or perhaps some sort of secure courier service if even the plane trip is too much.
We need some long term studies of the grief accumulation of a cleansed grief seed, but normal grief seeds don't resurrect into witches very quickly in general as oftentimes meguca will keep a small supply of grief seeds without prompting that issue. From this I don't think that their grief generation rate
can be that high, otherwise it would be a constant issue.
The possibility exists of some sort of
reverse grief spiral where grief seeds generate less grief at near full grief instead of the positive feedback loop typical in meguca witching out, I don't find that terribly likely though.
