Unless parts of the body are covered or pressed hard on a hard surface...then Livor Mortis does not appear that's why in an early photo you put up you can see only parts of livor mortis on the man's back.
And I've explained to you that Sheila were not in the position we see her when livor moris appeared. The top side of her arms...now showing...was on the ground....hence livor mortis.
There is no need to keep showing me how livor mortis settles, just remember she wasn't on her back soon after death. Do you really believe Sheila's position shown doesn't look staged. It looks like she died perfectly straight! Only her head in an different angle, and the back of her nightdress is pulled up where she was positioned after death. If Sheila had shot herself twice the rifle would have fell away from her neck the same time she fell back.