1. Boat is big and comfortable. Big dive deck with plenty of space for your dive and camera gear.
2. Accommodations - it's a boat. Rooms are reasonable size with charging points, and I never found hot water to be an issue while showering.
3. Late August - pack sweats of some kind. It probably won't be "cold" as such, but it will probably be quite windy. Daytime temps right now are around 25-26C, but it's down around 10-11C at night. Add in the wind, especially after doing 5 dives, and you'll be wanting to wrap up a bit! Full length wetsuit recommended - I dive a 5/4 mm at this time of year.
4. Crew are awesome, and they'll chat to you once you're aboard about what you want. If you want to just go off and do your own thing with a buddy, you can. If you want a bit of guidance, they usually have 1-2 DM's in the water on any given dive that you can follow around. It's all very flexible depending on your experience and comfort level in the water.
5. Tipping - in Australia this causes a bit of controversy. We don't really do it, because minimum wage here is actually enough to live on. There will be a tip box at the end of the trip when you're settling your on-board account for people to contribute to, but please don't feel obligated to tip here. Australian's will rarely tip at home, and even then, tend to only do so if someone goes above and beyond.
6. Photography - also a photographer here...There's not much macro on these trips. You might spot a handful of nudis towards the end of the dive as you're coming back up, but by and large, it's all reefscapes, fishscapes, and sharkies.