When I did research in the good old (bad old) days, this is what I came up with:
All their convoluted reasoning hinges on the 1914 date. According to their explanation of the "seven times" of Dan. 2: End of the Gentile times (7 x 360 = 2520 years), from 607 BCE to "fall of 1914." If you add 3 1/2 years to that, you hit 1919 (see "time, times and half a time" of Dan. 12:7 and 1260 days = 42 months of Rev. 11:2, 3). All of these scriptures they apply to the war period, 1914-1918.
Now add to the mix the 3 1/2 years of Jesus' earthly ministry. Jesus judged the temple at the beginning and at the end of his ministry (cf. 1st cleansing John 2:13-17; 2nd cleansing Matt. 21:12, 13; Mark 11:15-17; Luke 19:45, 46). So, according to WT reasoning, Jesus' presence would start at the end of 1914. Three and a half years later he would inspect his temple, according to Malachi 3:1. This brings one to 1919.
During my JC I proved to them that above scriptures cannot apply to the 1914-1918 war period. E.g. At Dan. 12:7 it says that the hand (=power) of God's people will be shattered (like a clay vessel). In Rev. 11 the beast that ascends out of the abyss, which they identify as the League of Nations and the UN, which kills the two witnesses, did not exist during the 1914-1918 period, etc. But to no avail, I was disfellowshipped as an apostate for my trouble.