That's a common strategy to us, but you don't even have to use your 2-hour really... and no potions...
Just go in on darksday (for less sleep resists), run up to the area where he stands, sleep him, dispel, and nuke.
Sleep -> nuke -> sleep -> nuke, rinse and repeat.
Once you are out of MP, just convert and cure yourself. Keep nuking -> sleeping. If you run out of MP at this point, sleep him, run 40 yards away, and /heal. Once you see him wake up, stand up and sleep him again. Then nuke him to death.
Remember:
- Buy potions like crazy just to be well-prepared. Whatever you don't use you can sell back.
- You are not there to beat the time record, you are there to win. Keep this in mind.
- Don't panic, panicing more often then not makes you perform stupid misstakes.
- Save your 2-hour for when things start going bad. That's what it's for anyway, to get you out of sticky situations.
Doing this I won on my first try, no potions nor 2-hour used. Just go in well-prepared, with a the aim to win. Not to set a time record. And remember to always stay at a 21 yard/metres (whatever FFXI goes by) distance from him every time you cast an offensive spell. This gives you enough time to resleep him before he gets time to hit you more then once.
And refresh Blink/Stoneskin/Aquaveil whenever you feel the need to do so. (Phalanx is really not needed... I didn't use it atleast)