Setting and explanation of eye relief video

I woke up from watching a youtube video on Magpul PRS stocks and the linked video was on.
The video is about setting up AR’s for PRS shooting but at 16:33 there’s a very good tutorial on seetting eye relief. Pretty informative also with parallax info.
There’s also some good info on trigger positioning on the finger right after length of pull at 15:45.

I thought it was some good information.
Take it for what it’s worth.
Actually the entire video is pretty good.