The problem with your analysis is that your are using the wrong verses to figure out what a generation is in the Bible.
A more appropriate verse for this situation would be Numbers 32:13, "So the Lord's anger was aroused against Israel, and He made them wander in the wilderness forty years, until all the generation that had done evil in the sight of the Lord was gone."
Forty years has to do with the judgment of that generation. "This generation" of Matthew 24:34 is speaking of the generation of the children of Israel in the 1st century who rejected Messiah and had Him put to death. "And all the people answered and said, 'His blood be on us and on our children.'" (Matt. 27:25).
Lindsey and Smith had the correct timing. Their error was that they were off by nineteen hundred and ten years or so as to when to apply the timing.
When I posted my "thoughts" I think it was pretty clear that they are thoughts, not something I absolutely hold to dogmatically.
Then consider my comments as more information by which you may refine your thoughts.
IF you KNEW Christ were to return next week, how would that change your prayer life? Who would you call to meet for lunch or dinner, to share the gospel?
But we don't and still we should. That's why schemes based on calculations about modern, secular Israel as some indicator for Jesus' return are so detrimental to the life of the Church.
Not necessarily- It can be argued that the generation that offended the Lord was already in existence. Therefore, the punishment was levied against everyone over a certain age, or relatively, the generation in charge at the time. Folks under the age of 30 years, certainly those under the age of 20 years likely did live to see the promised land.
There are legitimate reasons to use the longer generational definition. Of course, as my previous post on this thread suggests, I believe it all to be speculative until the next mile marker approaches. We see through the glass dimly.
What is unquestionably a sign is the establishment of Israel as a nation for the first time in 2000 years. That has occured.