If we both agree as to what would actually be happening in these hypothetical scenarios, but disagree about what we value, then clauses like "patternists could be wrong" refer to an orthogonal issue.

Patternists/computationalists make the, in principle, falsifiable assertion that if I opt for plastination and am successfully reconstructed, that I will wake up in the future just as I will if I opt for cryonics and am successfully revived without copying/uploading/reconstruction. My assertion is that if I opt for plastination I will die and be replaced by someone hard or impossible to distinguish from me. Since it takes more resources to maintain cryosuspension, and probably a more advanced technology level to thaw and reanimate the patient, if the patternists are right, plastination is a better choice. If I'm right, it is not an acceptable choice at all.

The problem is that, so far, the only being in the universe who could falsify this assertion is the instantiation of me that is writing this post. Perhaps with increased understanding of neuroscience, there will be additional ways to test the patternist hypothesis.