Hi Matt
we're average plodders ... and went up to the Blue Mtns a couple of weeks ago to do some of the major stairs. As well as the many hills, the main staircases to climb are The Golden Staircase .. up to CP1, and Nellies Glen, up to CP 4. Both sets of steps are not a bit like the stairs you would have trained on .. they're stone and logs, muddy, slippery, uneven etc.
I didn't count the steps, but it took us 12 minutes to walk at a comfortable pace up the Golden Stairs. Another regular poster on the Face Book 'Unofficial Australian North Face 100 site'
http://www.facebook.com/pages/The-Unofficial-Australian-North-Face-100/183848461633391 reports that Nellies Glen has 505 steps.
The other big one of course is going down the Giant Staircase behind the 3 Sisters. I don't know how many steps there are but I think it takes around 10-12 mins to get down them. They are mostly metal, but very steep and small, and slippery in the wet. You really don't want to try and rush down them.
You might want to hit those uni stairs a few more times over the next 3-4 weeks .. any practice will fare you well for the NF trails

If you Google the names of these staircases I'm sure you'll see plenty of pics and info .. they're popular walks in the Blue Mtns

.. I hope that helps!
Good luck with it,
Jaci.