If you want people to sign up for cryonics, the method with by far the strongest conversion ratio is to train them from scratch in advanced sanity techniques.

With all due respect, where's the evidence that reading LW/HPMOR trains people in advanced sanity techniques?

It seems reasonably plausible that, for example, Harry's argument with Dumbledore primes people toward "death is bad". If they hang around long enough and read what LW has to say about cryonics, that priming tends some fraction of those people toward subscribing to cryonics, without them learning anything about e.g. Bayes' law.

But I don't know, I don't know the numbers. What's the readership of HPMOR versus Alcor's 2011 signups?