As a rule of thumb the smaller the space
(often a triangle, though can have four or more sides) that encompasses the
presumed fix the better. This makes intuitive sense; since as you note perfect
LOPS would coincide at a single point, the fix.
but perhaps that should have been:
“perfect LOPS would
coincide at a single point, the actual position.”
The fix would be the actual position: grace of perfectly plotted results,
of perfectly reduced perfect sights, using perfect methods; and the perfect
sextant and watch, recorded and reduced by the perfect navigator, who just
happens to be having a very nice day, with but few of those pesky clouds. With
all that stuff to go wrong its something of a miracle that so many sights do
give useful (accurate enough) information.
But information isn’t knowledge and knowledge isn’t wisdom …