I grew some Opuntia robusta from seed last year and I put them in the fridge for 3 months in moist peat moss prior to germination. I got several dozen seedlings from that, but overall germination rate was very low.

This year, I have thousands of seeds, and I want to maximize germination. I see a lot of online guides recommend cold stratification, but I'm not sure this is correct. For one thing, a lot of opuntia (including O robusta) are cold sensitive. If it freezes, they will die. So, why would their seeds require cold to germinate?
I am wondering if anyone here has more info on this?

If not, I'll have to do some tests over the winter to determine the best route to take. I'll test cold stratification, physical scarification (sandpaper), acid scarification, and then cold +scarification to determine best germination rates. Because this process takes several months, it would be nice if someone had already done this.