The question of whether I want to be immortal or save 28 mortal lives, is not one I've seen much addressed, and not one that I've yet found a satisfying answer to.
I find the answer "be immortal" satisfying, personally. Your mileage may vary.
May I ask what reasoning/evidence lead you to that conclusion? I'm sort of viewing it as a trolley problem: I can either kill my immortal self, or I can terminate 28 other lives that much sooner than they would have.
(I'm also realizing my conclusion is probably "I don't do THAT much charitable to begin with, so let's just go ahead and sign up, and we can re-route the insurance payoff if we suddenly become more philanthropic in the future")
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: