The vertical trail of blood from Sheila's first wound , well near vertical) is quite distinct from the main flow to the right from the wound.
The lesser amount of blood that flowed vertically is most important evidence. It seems that this flow may have been wiped/cleaned a little at some time. Possibly from contact with the neckline area of her nightdress. Some of the more prominent blood staining on the neckline area may have been because it lined up with the vertical flow from the wound and has shifted due to movement of the nighdress in relation to her body.
Even so..for such a wound there is a relatively small amount of blood that has flowed vertically as most of it has flowed more to the right. The vertical flow is not great so it means she cannot have been in the vertical position very long at all. A good chance that this would have been well under a minute.
In my view its not possible to define if she was upright when the first wound was inflicted and thus the vertical flow occurred shortly after infliction or whether the flow occurred a little later as a result of her moving or being moved.
Once Sheila was shot to the right side of the neck, she used the fingers of her right hand to grasp the lower wound site, and at that stage blood which ran from the non fatal wound ran across the top part of her hand and created the large triangular bloodstain on the top right hand side of her nightdress. You can tell that the vertical run of blood from the lower non fatal wound (bullet PV/20) and the triangular bloodstain on the top right hand side of the nightdress appear to run in the same general direction, and therefore must be linked together and associated one with the other...
The folded right arm and hand operated as a bridge to allow the blood from the lower non fatal wound on the right side of the neck, to become deposited by virtue of the bridged hand/arm movement onto the nightdress...
This could not apply to the upper fatal shot because the direction of blood flow from the upper fatal entry wound site goes in the wrong direction - or in other words, because the shot under the chin was instantaneously fatal, it would not have been possible for Sheila to use her right hand to hold the fatal wound site under the chin so that blood ran upon it and created the triangular bloodstain, on the nightdress, aforementioned...
If Sheila's hand was used at all to help displace the blood from one of the wounds to the nightdress in the terms described by me in this posting, it could only apply to the first non fatal wound, since Sheila survived that first shot...