I recently got a phone call saying that, if I recall correctly, around a quarter - or maybe it was half - of all Alcor's cryonics signups this year, are originating from LW/Yudkowsky/rationality readers. 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.

Your conclusion doesn't follow from your premise. Moreover I don't know what you mean by "advanced sanity techniques." I agree that you've probably increased to number of cryonics signups substantially but I doubt that increased rationality has played a significant role.