The impression of width also comes from the angle of the sides of the
falls at their base (those that are rounded or close to straight look a
lot wider than those that are even slightly convex), how "flat" the
falls are when fully open (as opposed to being arched up even the
slightest bit, which can hide a narrow base), and how ruffled the
standards are (which can also hide a narrow base).
And smaller flowers aren't as wide as bigger ones ;-)
My rule of thumb for determining width is my thumb. If the space
between the hafts of adjacent falls is more than a thumb's width, it's
not an "improvement" of haft width in the lines I'm working with.
I don't actually like really wide (especially overlapping) falls, but
don't care for the narrow ones, so am usually hunting for breeding
material to add width, or, like you say, the impression of width.
This one certainly has more than it needs ;-)
<Do you ever find that haft width is deceptive? That is, that the
impression of some blooms is of having wider hafts than some that
actually have wider widths? I do, and I think it's caused by how the
standards sit over the falls.