They upload pretty much at 8:15am every morning. Because I work nights I aim to get in line at 8am and I am generally one of the first people there.
I know it is going to be a public holiday, but the crowds this season have been very manageable. I remember spending a good 35mins in a line once or twice last season. I found if you get first chair up get a good 3-4 runs in before it starts getting busier, by then they generally open up the alpine. A few runs in the alpine and its time for an early/late lunch so you can be riding again while everyone else is eating
Re. public holiday, this weekend is the public holiday. Crowds today (and yesterday) have been crazy, and I'm going nowhere near the mountain tomorrow (half price tickets, gonna be busy!). But as I read it the OP gets here Thursday, i.e. next weekend. Shouldn't be as bad.
Agree with the rest of what you say, crowds have been very manageable the whole time I've been here. Only once have I hit queues comparable to Europe and that was only because Symphony and Peak2Peak were closed until an electrical storm cleared. Even then the queue moved (and the birds kept us entertained!). And queues are much less annoying than in Europe - people are polite, friendly, don't run over/into you, jostle or skip.