I have found that the LCD screen is not very forgiving and needs safety zone settings so you don't cut off important video. What safety zone settings 80 or 90 percent are being used?

Actually the LCD crops in from the left and right but only a tiny bit from top and bottom. It would better if you could see the entire image in underscan, but that's the way it is.

Depends upon what you want. I leave the 80% guide on and if I stay inside the bounds, I'm good.

I think what you really want to know is whether the guides are accurate. They seem to be but I've never tested them.