There's one thing that we haven't checked yet and I don't know how to do
that. When you evaluate :height first you get a line height of 30 which
scaling should reduce to 15 without loss. When you evaluate :family
first you scale twice with a loss. I have no idea whether this has any
impact. You can try whether either of the following
(progn
(set-face-attribute 'default nil :family "Inconsolata LGC")
(set-face-attribute 'default nil :height 110))
(progn
(set-face-attribute 'default nil :height 110)
(set-face-attribute 'default nil :family "Inconsolata LGC"))
causes a different shrinking behavior but I doubt that it will reveal
anything useful. So I ran out of ideas ...