The southeast spread of Iberian?

There's a recent article about deep structure in Iranian-speaking populations, far deeper than the age of the Iranian protolanguage itself. Even of Indo-Iranian.

I was most interested in the Daylam and Tabari regions, up along the Caspian shore toward historical Atropatene / Adarbadagan. To that, here's Nasidze's 2006 article on their languages and peoples. The claim: genetically the men were "South Caucasian"; the women, Pahlavis. The women won this one, and now the people speak Gilak. (Well, okay; they now speak Farsi with a Gilak accent - but Gilak used to be a language, in living memory.)

Still: Old Gilak retains some "South Caucasian" structure. So does Old Tabari.

One point I'll point out: this doesn't always happen. Sometimes the men win. That happens when the male language has extreme relative prestige, like the Bell Beaker (ItaloCelt) language or like Islamic-era Arabic or like Spanish in Puerto Rico. And sometimes the men and the women end up splitting the difference: there's a male language and a female language. This - I am told - happened in Greek-occupied Milawanda. Or there is a male register and a female register like in Sumerian. Maybe even the male and female genders in Semitic started out this way, I don't know.

But it does often happen that a force of male invaders give up and take the language of their conquered peoples. The Huns spoke German and the Avars spoke Slavic. R1b males in Basque Country speak Euskara. The "Urnfield" crew were certainly Gauls up north; but once in Etruria, they spoke like Etruscans spoke. And let's not even get started on China.

I am interested in knowing WHICH "South Caucasian" language the Gilak men first spoke. The claim is that they are speaking Kartveli. Not Hurri, which I would have expected this far south.

The last breakdown of this Caucasian language family I can find (right now) is that of Georgi Klimov 1998 - and I'm getting this from Wiki, at that. Klimov has Svan, on the Caucasian fringe, breaking off deep in the early Bronze Age. Then in the Iron Age, around when the Urartu state was running, there's the next split: between Iberian (now, "Georgian") and the coastal Lazican languages. Did Urartu conquer the Black Sea coast and leave alone the Kura watershed? How far down river did the Iberians dare?

South of the Kura when we next see the Araxes plain, in Late Antiquity, it's full of Armenians getting thoroughly Parthicised. "South Caucasian" isn't heard anywhere there.

Maybe the Gilaks and Tabaris stem from Iberian exiles and/or adventurers who took ship and settled the Tabaristan, beyond easy reach of the Parthian Empire.

UPDATE 10 PM MST - This Nasidze et al. 2006 article depends on Donald Stilo's work on contemporary north Iranian dialects. In 2005, that is "Iranian as buffer zone between the universal typologies of Turkic and Semitic", which I've read on Google Books. Google let me read the whole chapter, so, I am grateful for that. And I can report : this article alone cannot bear the weight which Nasidze's crew place on it. The earlier one is "The Tati language group in the sociolinguistic context of Northwestern Iran and Transcaucasia" (1981). Thirty eight years ago.

Yeah, I'm going to stick that ? mark on the end of this post's title.