Lovely piece, tack for showing us.
I agree with you that early Murano is a likely option - if you find a vague mark saying "Italy" in script you're in luck. It seems to be very much in the style of Cappelin Venini in the 1920s - though others have made similar things. In any case, this shows top glassmaking skill as found in Murano, and the model is classical Venetian.
Hope you'll get it positively IDd. "Optic Blown" btw is the correct translation.