Venetian Coat Sleeves

Work is coming along on the Venetian coat.  I've got it cut out (always an important first hurdle to overcome) and the center back gore is put in.  I went with a basically rectangular construction, based on the pattern for Ottoman style coats given at the Renaissance Tailor because this seems plausible and I don't really have time to do a great deal more research.  I did however skip the weird underarm gore thing, partly because I don't have time to figure this out and also because it does not make sense that this is how the Venetian version of the coat would be cut.

Here is my thinking...the lady in the Titian portrait is clearly NOT wearing actual Turkish clothing.  The fabric is plain satin, which as far as I know was not a big thing in the Ottoman Empire at the time, the trim is wrong, and the fit is more constructed that what you see in the few illustrations of contemporary coats I've looked at.  So, my thought is this is an Italian interpretation of what the Ottoman's wore, and thus cut more like Italian cloths. Given that, I've cut the body of the garments in two rectangles with triangular gores at the sides and center back, which squares with how similar robes are cut in Janet Arnold (sort of, it's at least plausible and makes good use of the fabric).

Which brings me to the sleeves and upper body.  The original coat the lady I am making this for made is cut just like your basic early period tunic, with honking big gores under the arms (see the picture).   This is all well and good, but produces a much looser look around the upper body than you see in the Titian painting, and as far as I know wasn't a commonly used construction method in the 16th century.  So...what to do?  A shaped armscye?  Something more like the grand asiette style sleeve I've used in my fitted gowns, but looser fitting?  Clearly some sort of set in sleeve is called for, the question is weather I want/need to use the gore in the back, and how set in it should be.