Radu is obviously one of those "modern horary astrologers" who cannot delineate a simple horary chart without bringing the outer planets, Chiron, Lilith and Sabian Symbols into play.

but it's hard for me to believe Radu didn't get it from a pre-1800 source.

For me it's not hard to believe at all - the factors I've just mentioned he also could have never found in the pre-1800 traditional astrology, yet he uses those on a regular basis.

Greetings,
Goran