Heads-up Tournament Win %

What is considered a good winning percentage for heads-up 2 player tournaments among the best players? What is considered sustainable? I know these numbers exist for multi-player ring games, and are highly focused on by players looking to make money there. Remember, I'm not asking about BB/100 for heads-up cash games, I'm talking about one on one SNGs (regular, not turbo, although it doesn't necessarily really matter).
Is anyone well experienced in the heads-up tournament field? What experiences have you had with playing it regularly?

I'm not too sure what a good win percentage is for headsup matches, I would assume a "great" headsup player would win about 8 out of 10 matches. I think if you can win 3/4 your doing good, as long as it is consistent.

Not to sure either. But yeah.. 3/4 would be a good haul as long as you are consistent.

Although I am lacking in experience i think that winning around 3/4 to 4/5 would be a great percentage.

I don't know from experience what's sustainable (I suspect it swings a fair bit depending on the player), though I'd like to find out myself at some point - heads up is fun

What I do know, however, is a quick bit of math:

Assuming a rake of 10% on top of the buyin, and no money added to the prize pool:

50% win rate = losing one buyin per 10 matches to rake
60% win rate = profit of one buyin (without rake) per 10 matches
75% win rate = profit of four buyins (without rake) per 10 matches

Adjust those figures slightly for the rake on your site (I think on Full Tilt it's actually be 7.5% for HU SnGs?) and compare them to your win / profit figures at other games, then see if you think you can sustain the win rate required to make HU more profitable than your regular game.

Wow Cool! It was great to see your posts. Currently Heads Up No Limit matches on Full Tilt are just about the only poker that I play online. I will occasionally do a MTT if I have the time, but that's only about once a week or so (I play live several times a week.)

I can tell you that I have had reasonably good success with these types of SNG and it is a great way to strengthen your game and try different strategies. I started out playing the $5 Heads Up NL Tourneys and after 20 had won 18 of them. I decided to move up to the $10s. I won my first 10 in a row, then I settle in to a win rate of about 8 out of 10. After about a month, I moved up again, this time to $20. My win rate dropped a little, but was still acceptable at about 7 out of 10. I decided a couple of days ago to try $30. I started going about 50/50 so I moved back down to $20. I'll stay there for a while and see how it goes.

I'm looking into playing a ton of these in the near future, so I'll let you guys know what types of numbers I'll come up with.