How to set r.sss.scale to 1 by default & eye materials

I have been trying to figure out how to do character rendering recently and I tried adding Subsurface Profile for the skin following this tutorial:

It took me a good while to get it to work, because it seems r.sss.scale is set to zero by default. I thought it wasn’t working because there was something wrong with my material set up, first. How do I set r.sss.scale to be 1 by default? I have tried to look into the .ini files, but can’t figure out where to put the command there.

Another, bigger question is the eye material. I come from Source Engine and eyes work quite differently there. For one, the eyes are not a sphere model inside the head, disconnected from the rest of the mesh, but connected polygons where the engine handles the UVs. I am not super familiar how I should set up the eyes, how complex the mesh should be, should they be separate model assets, and most of all, how do I set the material for the eyes? I tried searching it and a lot of the answers were either from a lot older branch of the engine, or were referring to the content examples. But I couldn’t find any human eye materials in the content examples. The only example I found there was eye of the Sauron type of thing. There was another forum where they linked to some example material script screenshot that was so low res that it was impossible to read. Also, how are eyes turning normally done in Unreal? Should they be part of the skeletal mesh weight map with bone for each eyeball? In Source the eyes worked with the facial expression system so that the eyelids moved when the eyeballs turned up and down, but that might be too complicated for what I am trying to achieve right now.

Is there any good recent / up to date tutorials how to do good looking eyes in Unreal?