Fantastic resource you've created there Justin - worthy of its own webpage or IIS write up.
One thing you may have over the rest of us "Southerners" is signal to noise remember. I suspect your skies are darker than most, so even in the higher noise cat's you have labelled, the signal to noise you collect from a dark sky site could still be very good.
With any sort of light pollution (I live in Bris Vegas
) the S:N equation quickly goes pear-shaped. It was a true revelation for me seeing the difference between ISO800 S:N at Qld Astrofest (and even better at Barambah) to the best shots I'd managed from the 'burbs. Up until that time I had been so stoked with what I could with long exposures, DSLR and pollution filter and still coming to grips with what you've done here in a FAR more piece-meal fashion.
As long as you're doing decent darks/flats/bias (or however you deem fit to calibrate your frames) and getting total exposures over a couple of hours I suspect with the S:N you'll get it won't matter if you're up in the longer exposure time for ISO 800. Suggest ISO 400 for brighter objects and avoid 1600 unless you're in a hurry.
Couple of other thoughts - perhaps consider use of external (non-battery pack) power and having a fan running on the camera if you're really pushing for a bit of advantage (must confess I've never bothered with either and Brissy nights can get pretty warm). Then again I'm not holding my breath for a David Malin either...
