This is what I know. I haven't really watched the episodes on either the Shout Factory DVD sets or Disc 2 of the "Classic Game Shows And More" DVD set, so a few dates are uncertain. Also, I'm pretty sure there were some variants.
** How many total variations of the main question game did the show have and what year(s) did they appear in?
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1947-52?: Three couples start at $20 and can bet all or part of it on four questions, with a maximum of $320.
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1952?-53?: Couples start at $0, but select questions ranging from $10 to $100 (in $10 increments). Maximum is $340, and wrong answers carry no penalty.
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1953?-56: Same cash scale as before, but couples now start with $100 and a wrong answer halves the bankroll. Maximum is $440, minimum is $6.25 (and several couples got the latter, leading to a really easy question for $25 like "Who is buried in Grant's Tomb?" or "What time is it when both hands point to the 12?").
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1956-59: Two couples answer questions until they get two wrong or four right (both consecutively) for $1,000. (Debuted on the first show of the 1956-57 season.)
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1959-61: Couples answer four questions selected by hand from the "Question Tray" valued at $100, $200, or $300 with appropriate difficulty. $500 is needed to win, although the maximum is $1,200.
** How many variations of the final round did the show have and what year(s) did they appear in?
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1947-56: The highest-scoring couple plays one more question for the jackpot ($1,000 plus $500 for every show not won; I've seen it go to $3,500 once, but don't know if it was won). In the event of a tie, the couples write down their answers and the jackpot is split depending on the number of correct answers; at least once (early 1955), all three couples managed to score the maximum $440...
But nobody won the $2,000 jackpot.*
1956?-59: Couples who succeed in winning the $1,000 can elect to risk half on the $2,000 wheel; if the couple correctly picks what number the wheel will land on, they play for $10,000.
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1959-61: Same as before, but now the couple chooses a second number for $5,000.