Just read your McNokaird article and a nice piece of work it is. Congratulations! It is really very good.
I would add as a codicil to your thesis, however, the following:
Alexander MacLean Sinclair was an amazingly well-connected, well-respected scholar both in English and in Gaelic. His work was published both here and in Scotland at the turn of the century (His 500 page tome on the MacLeans is still in use today) and it is a remarkable achievement when one also considers that the man grew up on an impoverished farm in one of the poorest counties in Nova Scotia (still is). This does not mean that he could not be wrong nor does it mean that we do not have new information that he did not possess. But......I do not have the Gaelic and I do not know if you do but it would be nervy of me to contradict Professor Sinclair (a native Gaelic speaker and Gaelic academician) even 100 years after the fact and state categorically "The Sinclairs of Argyll were not shinglers". Similarly, I will not argue with your thesis that they must have been smiths. "Craftmen" or "people of the craft" I would like to think might include shinglers and if you don't think there's an art to shingling, try doing your own roof next time it needs one. There is veritable skill in roofing and I should know, I am a contractor and I value my roofers as my brothers.
Professor Sinclair, I think would agree with your general thesis that the Argyll Sinclairs are a different "kettle of fish" and the proof of that is his statement that they are "out-and-out Highlanders". My opinion is, as I have said elsewhere, that a connection may well be there between the Rosslyn-Caithness Sinclairs and those of Argyll but that opionion and 5 cents would have bought you a coffee in 1946. Whatever the truth of the connection or not, our Argyll brothers and sisters are members of our family and nothing can change that.
Juli's remark is on the money when in response to "Sinclair's by mistake" she responds that, looked at another way, Norman Sinclairs have no claim to be Highland.
Yours aye, Rory