Answers
If $1575 bets the $270 and the two $1600's match the bet, the situation is the same as betting all $500. Right?
You are right about all three betting the 270. However, the players with $1600 are most threatened with defeat by each other because they are tied for first. Most of the time, they figure they can win if they outbet you on the last round but they probably aren't worried about you but they are most likely worried about each other.
So, what does the first $1600 bet?
The first $1600 player is at a disadvantage because he can be outbet by the second player with $1600 unless he bets the max. So his best chance is to bet the max to make sure the other player can't gain ground in the event of his win.
The last?
The second $1600 player should outbet the first player with $1600 but both should wager at least $250 to stay ahead of player with $1575 if he wins.
If first 1600 bets the $500, what does last do?
He should bet $500 as well lest he be knocked out by the other player's win.
If $270, what does last do?
Last should bet $275. He will beat the other 2 if he wins the next hand. Any less and he can be beat by a win.
The easiest way I can see to hold any lead with minimal risk of being beaten by another player is to try to establish a lead difference which is equal to (max bet + (2 x min bet)). This will allow you to bet the minimum on the last hand and keep lead even if you lose and they win the max bet. E.G., you have a lead of $520 in this scenario and you wager $10 and 2nd pl. wagers $500. You would win by at least $10 if you lose and he wins.
As you can see, a good way to play tournaments is to try to meet certain goals along the way. It's easiest to work out your goals backward. Goal one is to be ahead prior to last hand by the formula suggested above. Also, you should know the average tournament winner's BR so you can try to get your BR as close to that figure by about 4-5 hands PRIOR to the end of tournament. If you achieve that goal, then you can play the last few hands according to the other players BR. This gives you a few hands to try to outsmart the other players, especially when you have the opportunity to wager last.