Include everything with a preview which is non-proprietary.
When more than one image with the same filter is available, pick the one
with the longest exposure time. If that includes more than one image, pick
the most recent one.
Definition of individual pointing
The STIS 50CCD aperture has a 52"x52" field of view (FOV), while the
other visible apertures have a 28"x52" FOV. The definition of
individual pointing, following what assumed for WFPC2, could be that
of a circle centered on the position with radius corresponding to
1/4 the size of detector, and therefore 13".
The MAMAs have a 25"x25" FOV, so in this case the definition of
individual pointing should be that of a circle centered on the
position with radius of 6.25".