Karnewarrior
Leastmost of the Hanged Man Arcana
It's probably best to think of the incubators as closer in psychology to a hypothetical AI than a biological alien; which is probably by incubator design in some way.While I'm no expert on PMMM, it seems to me that the Incubators will follow the letter, if not the spirit, of any agreements made. We may not have been allowed to rules-lawyer our Wish, but there's nothing stopping us from plugging up any loopholes we can possibly think of.
Also of note is that, while their methods are absolutely horrifying, the goal of combating entropy does not seem to me to be bad; even if the Incubators only want to preserve their slice of the Universe, so long as they leave everything else alone, I'm fine with that. As such, I feel that a deal that helps QB far more than it helps us (but that does still help us) is merely sub-optimal rather than bad.
Furthermore, Homura could potentially be used as a sounding board to help make sure that any deal considered is safe. We would probably need to explain the Kyubey-collective's ultimate goals, but I don't really see too much of a problem with this.
If that is the case, then simply asking kyuubey if there is a configuration of grief that would be more efficient as energy than the sort they extract from grief seeds is a positive for /both/ us and kyuubey. There are really three possible ways for the answer to go, and they can only be neutral or positive. Either:
1) there is a plausible, moral way to create "clean grief". In which case, we put in the requisite work and kyuubey becomes a business partner. Net positive for both sides.
2) there is a plausible way but it's immoral. We refuse to do it, kyuubey has another data point for his human psych class, and we have an answer to our question. Neutral result.
3) there is no way to create "clean grief". We don't bother throwing more mental energy towards something impossible, and we may earn a coobie brownie point for at least trying to help. Neutral end.
It makes sense to at least ask about it next time we science, and if it's possible there may be little reason not to try to do it then and there. Kyuubey is a slippery bastard, but he's a slippery bastard we know the agenda of. If we can make that agenda work for us, kyuubey has little reason to lie to us or omitt potentially damaging information. And the incubators are bigger on reason than on being slimy pricks.