Paul, I don’t know if anything here will address any of your thoughts.
http://www.astro.cardiff.ac.uk/research/gravity/tutorial/?page=4blackholecollisions For example:
“Chirps and ringdowns
Gravitational waves from a binary are predominantly emitted at twice the orbital frequency and carry away the binary's energy and angular momentum. Since the system loses its rotational energy, the two black holes gradually inspiral towards each other. Black holes that are closer together emit more radiation, thereby accelerating the inspiral. This produces a characteristic chirp waveform whose amplitude and frequency both increase with time until eventually the two bodies merge together. Prior to merger, the two black holes approach each other at speeds very close to that of light; their collision will be astounding.
The merger will result in a highly deformed single black hole which rids itself of its deformity by emitting gravitational radiation that is characteristic of the mass and spin of the final black hole. This is called the quasi-normal mode or the ring down signal. Laser interferometric detectors, such as LIGO, GEO600 and Virgo, should be able to detect the waves from the last few minutes of the binary's evolution. The ring-down signal is not unlike the radiation from a bell that is stuck with a hammer except that black holes are far more simple objects than a bell and the frequency and damping time of the radiation depends only on the final black hole's mass and spin.”
