I think another promising intervention would be to persuade God to be a conditional annihilationist or support universal reconciliation with Christ. Abraham successfully negotiated conditions with God regarding the destruction of Sodom and Gomorrah with just a few sentences. Imagine what we could do with rigorous and prayerful BOTEC analyses! Even if there is a small chance of this succeeding, the impact could be incredible in expectation.

There's a lot to unpack there. One quick observation: in some Christian theologies, the question is completely intractable. (Note that I am not endorsing Calvinism!)

Eric Sampson published a paper on this in Oxford Studies in Philosophy of Religion. See here. 

Abstract: Longtermist Effective Altruists (EAs) aim to mitigate the risk of existential catastrophes. In this paper, I have three goals. First, I identify a catastrophic risk that has been completely ignored by EAs. I call it religious catastrophe: the threat that (as Christians and Muslims have warned for centuries) billions of people stand in danger of going to hell for all eternity. Second, I argue that, even by secular EA lights, religious catastrophe is at least as bad and at least as probable, and therefore at least as important as many of the standard EA catastrophic risks (e.g., catastrophic climate change, nuclear winter). Third, I present the following dilemma for secular EAs: either adopt religious catastrophe as an EA cause or ignore religious catastrophe but also ignore catastrophic risks whose mitigation has a similar, or lower, expected value (i.e., most, or all, of them). Business as usual—ignoring religious catastrophe while championing the usual EA causes—is not an option consistent with longtermist EA principles.

Not a popular topic among secular EAs, in my experience.

Thanks for your post! However I'm kind a priori worried about your underlying hell model:

You stated earlier that int_{-\infty}^{+\infty} f(x) = dx[/33], setting your baseline intervention of Insecticide-Treated Bed Nets being set at ^{+12*33)). 

I think what you actually meant was  int_{-\infty}^{+\infty} f(x) = dx[/32].

Happy to take a look at your spreadsheet, which due to the topic at hand, I assume is in excel not google sheets.