Thanks for your interesting reply.
As you probably are aware, 'Solaria Binaria' is but one book of a fifteen-volume series...(and I've read them all!), some repeatedly such as the aforementioned and including 'Chaos and Creation', 'The Lately Tortured Earth', 'God's Fire' etc.
Such a wealth of material!
Like yourself, I too have an interest in Solar System origins and for many years I fully accepted the Nebular Theory...until I came across 'Worlds in Collision' and subsequent volumes such as the 'Ages in Chaos' series and of course 'Earth in Upheaval'.
These ideas were further augmented by the recent 'EU' Theory and around ten years ago, I came across the works of Alfred de Grazia/Earl Milton et al in the 'Quantavolution' series.
'Quantavolution' is a term coined by de Grazia that indicates a sudden intense large-scale change in nature.
The model is essentially electromagnetic, non-gravitational and short-term in nature that requires only a million years or so in the lifetime of the binary.
The actual "planetary ages" cover a period of around 14 thousand years and with the actual Moon-birth episode occurring around 12 thousand years ago.
Velikovsky wrote of planetary changes (mainly the Venus and Mars episodes) from 3,500 years ago although his intended books going back still further, 'Jupiter of the Thunderbolt' and 'Saturn and the Flood' were not completed.
These works were subsequently investigated by Dave Talbott and others becoming known today as 'The Saturn Theory'.
I note your interest in the expanded planetary theory, especially with regard to an earlier proto-Saturn and subsequent.
That idea is worth consideration because according to 'Chaos and Creation' with regard to the birth of the Moon from the Earth, the event itself caused the Earth to expand.
The resultant vacant cavity left by the expulsion of mass (the now Pacific Basin) was quickly filled and an ensuing crack appeared on the opposite side of the earth giving rise to rapid separation of the land masses, resulting in what is understood to be the now much slower-moving plate tectonics phenomenon...perhaps a remnant of these past catastrophic events.
In the Saturn Theory, I believe Saturn gradually lost mass through a succession of parturition events, due electrical instabilities and therefore contracted over time.
For myself, I lean more towards the Binary Theory of Solaria Binaria than the 'captured' Saturn thesis, but that is my choice.
Many newly discovered planetary systems consist of close-orbiting binary's which appear to fit the thesis of Solaria Binaria.
Even the late Prof. Lyttleton concluded that 'when the super Sun erupted as a nova it divided into a close binary pair, whose primary became our present Sun; and his companion was a body about ten percent the size of the Sun'
This agrees with C.E.R Bruce (in 1944) and more recently, the evolving EU Theory.