When three advance from a table of six or less you'll almost never go with an aggressive betting strategy in the early to middle rounds. If three are advancing from seven you'll usually be conservative unless several other factors combine to favor a more aggressive strategy.
The relatively long 30-hand round in your tournament favors a conservative approach as well. The starting bankroll of four maximum bets favors a more aggressive approach. Weighing all these factors if I were playing that one I'd be a tightwad even if it paid 2:1 on blackjacks.
A word of warning about three-advance tables: If it gets down to five players and there are still several hands left, pay very careful attention to your opponents' chip stacks and how many hands are left. It becomes a very simple problem for the three who are in good shape to make sure they stay ahead of at least two opponents. They start correlating the short stacked players, who are then forced to compensate. I've been in many of these three-advance tables where everyone busted out except the three winners before the end of the round. Don't be one of the two that busts out early because you let yourself get too far behind.