I wrote all that stuff about Hingis' chances and then Peirce went and got knocked out by Benesova so all the stuff I rambled on about was pretty much irrelevant
But yeah, I think its worth waiting longer...she should get past Stosur(famous last words) and if she plays particularly badly there it might be time to lay off.
If she plays well though she should play Clijsters, and that should be a very tight match. You can either lay off before, or gamble that she might just win. She will probably need Clijsters to be playing below her best - maybe the injury problems flaring up, but she has a fighting chance.
If she were to win that the odds would obviously tumble again. Then I think it would be time to lay off, as I can't see her beating players like Davenport, Sharapova or Henin-Hardenne quite yet.