Keep topping up. When you win big, you maximise your winnings.
I find that setting artificial targets, such as getting back to level (for example) mean that you deviate from your A-game. If I see a player get back to level, and then get involved in a pot on a dangerous board, I"m going to be betting into them knowing that they are likely to be getting out of the way. After working hard to get level again, they aren"t going to want to risk a big chunk of chips immediately.
Just my thoughts. Your mileage may vary.