I am skeptical of the existence of any clearly definable sense of "the probability that you will witness yourself surviving the experiment" that (1) yields different answers for Everett and for Bohm, and (2) doesn't have excessively counterintuitive properties (e.g., probabilities not adding up to 1).

Probability that any you looking at the outcome of the experiment after 1000 runs sees you alive? 1, either way. Probability that someone looking from outside sees you alive after 1000 runs? Pretty much indistinguishable from 0, either way.

You only get the "probability 1 of survival" thing out of MWI by effectively conditionalizing on your survival. But you can do that just as well whatever interpretation of QM you happen to be using.

If I find myself alive after 1000 runs of the experiment ... well, what I actually conclude, regardless of preferred interpretation of QM, is that the experiment was set up wrong, or someone sabotaged it, or some hitherto-unsuspected superbeing is messing with things. But if such possibilities are ruled out somehow, I conclude that something staggeringly improbable happened, and I conclude that whether I am using Everett or Bohm. I don't expect to go on living for ever under MWI; the vast majority of my measure doesn't. What I expect is that whatever bits of my wavefunction survive, survive. Which is entirely tautological, and is equivalent to "if I survive, I survive" in a collapse-y interpretation.