I meant "simpler" in terms of some appropriately rigorous version of Occam's razor.

I'm yet to see a workable version of it, something that does not include computing uncomputables and such. I'd appreciate f you point me to a couple of real-life (as real as I admit to it to be, anyway) examples where a rigorous version of Occam's razor was successfully applied to differentiating between models. And no, the hand-waving about a photon and the cosmological horizon is not rigorous.

A simpler theory in my sense need not involve less work to make the same predictions.

Again, a (counter)example would be useful here.

Just to make sure: do you think simpler models (in my sense) are preferable? Or do you think our two senses are in fact equivalent?

That depends on whether simpler models in your sense can result in more work to get to all the same conclusions. I am not aware of any formalization that can prove or disprove this claim.