Refreshing article on the grammatical issues involved in reading John 1:1, also touching on the use of article in Greek.
This article is a pilot study on the feasibility of investigating the grammar, both in terms of words and sentences, of the Gospel according to John in a systematic manner. The reason is that in general the commentaries and even specialized articles have different foci, inter alia, focusing on the historical nature or the theological and literary aspects that the Gospel is so well-known for. In surveys of commentaries on the Gospel it becomes apparent that real grammatical studies are far and few between, and that there is a tendency among commentators to copy grammatical material from one another. More often than not, grammatical issues are simply ignored and the unsuspecting and trusting reader will not even realize that there is a dangerous dungeon of grammatical problems lurking beneath the surface of the text. Apart from that, the significance of grammatical decisions are often underestimated in studies of John’s Gospel.
https://www.bsw.org/filologia-neotestamentaria/vol-21-2008/a-grammatical-analysis-of-john-1-1/525/article-p91.html
Of course, the name should be Van der Watt, not Walt. I must have been thinking of Disney… 
Barry, that article disagrees with you fundamentally on some key grammatical and interpretational points. For example it asserts that the articular θεὸς at John 1:1b is a reference to the Father (p. 115) (or in Trinitarian parlance, to “the person of the Father”). You disagree.
Also, you have gone on record to say that “the main reason for having an anarthrous PN is to distinguish it from it’s subject.” I would like to inspect this rather strange (IMHO) claim by asking you follow-up questions. Here are a few, for starters :
(a) Are you saying that in a S (Subject)- PN (Predicate Nominative) construction the anarthrous substantive is always the PN ?
(b) If the “main reason” for having an anarthrous PN is to distinguish it from the S, what are the other reasons ?
(c) If both substantives in a S - PN construction are articular, how do you determine the subject ?
(d) If both substantives in a S- PN construction are anarthrous, how do you determine the subject ?
(e) If one substantive in a S-PN construction is articular and the other is anarthrous, what is the most important criteria in determining which one is the S ?
(f) If one substantive in a S-PN construction is articular and the other is anarthrous but definite, what is the most important criteria in determining which one is the S ?
These should suffice for now.
Ψευδονευτόνε, cum scientiam quem non attigisti simules, quid in tenui animo sit mihi non cura est.