John Carrier wrote:

When the Foxbat was the rage, we often practiced "snap-up" intercepts
in the F-4 and, as you indicate they were extremely critical regarding
geometry. The key was getting as close to head-on as possible so as to
be at R-max in your pitch-up.

How true. I've run simulations where target aspect just got away (and it
wasn't much to begin with). And even with horizontal geometry solved being
a bit late for the pitch one would never get the nose up fast enough to
center the dot. With Sparrow, it was imperative the missile get off in
medium altitude autopilot gain and with a lead-collision geometry wired at
launch.

It would still SWAB (Switch-after-boost), though.
With later missiles, your chances actually improved firing
from level (just at/inside Rmax); no snap-up equals no need
to recenter the dot; you're already there.

Any major inflight guidance corrections by the missile would drive
PsubK from fair to non-existent.

Agreed. Our simulator (WCS maintenance; APM-307) flew all
profiles with the aircraft tricked into thinking it was
flying at 44,000 ft, though. It was the one variable we
couldn't change without modifying the hardware...