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(1) Original Text (lost) = "Neutral text"
(2) binary split into two basic streams, Western & Alexandrian
(3) An early 'Lucian Recension' = a proto-Byzantine text
(4) further conflation of the two diverse streams into one mixed "Syrian text" (= Byzantine).
(5) further development of the circulating Byzantine text in language and style, and accruing of marginal insertions.
This linear model of descent has since been largely abandoned, because there is no real way to get to the Byzantine text by 'conflating' the Western and Alexandrian.
The real picture is far more complex, and more like the following:
Abberant texts like that of Vaticanus and Sinaiticus are just what they appear to be: Expensive and durable church copies made for public reading and worship services. Copies like these served as a combination "Bible" and Lectionary for public reading, and have many idiosyncratic features caused by the back-influence of the Lectionary stream in development.
*thanks to Nazaroo for the graphics!