Was there one material in particular or was it just all of them? I did the course with 5.1 not too long ago and was mostly able to follow. I’m taking a look at the 4.5 Principled BSDF, and there’s a section with a drop down for Specular that has a IOR Level and on the Sub Surface Scattering, if you switch it to Random Walk Skin, that has an IOR value, though I’m not sure if those will match exactly what he did there.
I was looking at that particular video and didn’t see where he used any of those values, Nor in the video before. He does talk about them more in the materials course he did, but I don’t think he uses those in this course so you should be fine.
