they could have retained the simple placement method without excluding portion of the images in their actual clipsprite capture.
To achieve the desired effect ( the Model peaking in from the side of the Screen ) A real screen on the side of the stage was used.
This then allowed for an Accurate Bounding Box, that the software could then Shift to the Side of a Users Screen.
It then didn't matter the Size of the Performer, or the Outfit, or an Accessory.
The Edge of the Bounding box would always be the same.
Math
Find center of screen
Find edge of users Screen
Width to edge = Edge - Center
Find center of clip
Find edge of Bounding Box
Width of clip = Edge of Bounding box to Center
Clip center = Screen Center
Shift Clip from center = Width to Edge - Width of Clip
That places the Clip right on the side of the screen.
It is the Same type of Shift Used to Have the Clip Seem to be On the top of your Task Bar.
It would have been technically impossible to do the same if the Full body was included.
There would have been no Fixed Bounding Box.
An example is when the Model wraps her fingers around the edge of the screen.
That is only possible to create, because there is an Actual bounding box.
Bit 6 or a Value of 64, is what the Software uses to classify a clip as in/out.
After that Bit is found, then the Header of the clip contains the bounding box metrics to determine the shift amount.