[A_K]

I'm in the minority here, because like you, I actually prefer limit tourneys. (Mostly because I'm a decent limit player but suck at NL).

Two tips:

(1) You really must play like a LAG when you're shorthanded, and HU you should just go nuts. I often win the low-buyin limit tourneys by playing tight until the end, and then just running over guys. If you play your tight agressive style HU (or three- or four-way) you will lose.

(2) My favorite heads-up discussion is in Hold 'Em Poker for Advanced Players. As it points out, a near-optimal strategy heads-up is to raise every hand (or nearly every hand) from the small blind. Unless the big blind calls a surprisingly large amount of the time (or three-bets, or check-raises the flop), the SB's strategy is profitable.