Rebbetzin Eris Odani Elyashiv referred to the Gra’s comments on the Zohar regarding the calculation that 5772 is mincha gedola before 6000 and the time that moshiach is destined to appear. I want to refer to the exact quote from the Gra to make sure I don’t misquote him. Do you have the reference?
There is a section of the Zohar called “safra d’tzniusa,” corresponding to Parshas Trumah on which the Vilna Gaon wrote a commentary. There, in Chapter 5, he writes (very much along the lines of what is already mentioned and established by many Rishonim and Achronim before him) that each day of the week corresponds to 1000 years of history. Therefore, the 6th millenium which we are in now represents Friday. That’s all he wrote on the topic. Based on that we would calculate as follows:
As with all Torah days, the night comes before the daytime. If the night is 12 hours (representing ½ of a halachik day), then an additional ¼ day brings us to midday (chatzos). That corresponds to 5750 in our calculation (1989/1990 CE), since 1000 years is equivalent to 24 hours, and 1 hour to approximately 42 years. According to halachah “mincha gedolah” can be said ½ an hour after chatzos. Therefore, it follows that 5771 was the mincha gedolah of history.