"Sancho's Atomic Trousers" schrieb im
Newsbeitrag ups.com...
Waves, virtually by definition, travel at the
rate at which change (in the configuration
of a given medium) is propagated in that
medium.

Thus it follows -- almost from definition --
that the speed of gravitational waves (a la
Einstein) is the same as the "speed of
gravity".

And if the former is in fact c, so must the
latter be.

No.
The "speed" of gravitation can experimentally
be observed by the speed that SGR transports
energy & momentum at least at multi-c (if not
even simultaneously). Cf Substance-relevant
Gravitational Resonance explained (1 page) in
www.sources.li/SGR-e.pdf.