If I understand correctly, both presentism and eternalism accept that spacetime can be described by the same coordinate system and following the same rules of physics. Moreover, both of them affirm that a huge amount of matter-energy (or information) exists distributed throughout space. The difference is that presentism posits that time is special in the sense that matter-energy only exists in a slice of time, that encompasses all of space. Whereas eternalism posits that matter-energy exists at all points of this coordinate system.
Now, my question is: can Occam's razor be applied in favor of presentism? The argument would go that both perspectives explain exactly the same facts and are compatible with all known science, but eternalism demands much more matter and energy to achieve the same explanatory result. Whereas presentism needs just a very tiny part of all that matter and energy to explain everything we see. Therefore it would seem that presentism would be the simplest theory. In other words, why would we need to assume much vaster quantities of matter-energy if we gain no explanatory power?