hi marty,
good to see you getting out there having a crack. the next couple of nights look good too for melbourne. looks like you have got your guiding down pat pretty well also smashing out 10 minute subs.
I'd give varying times some experimenting, with a light pollution filter I can only really push to about 3 minute subs. only with narrowband can I consider going close to 10 minute subs, even with the light pollution filter it can wash out the sky still with sky glow and make it really difficult to process (especially with the moon around). here is an example of M83 I did with 20 second subs (40x20secs) on my old goto dob
https://www.flickr.com/photos/803366...ream/lightbox/ (which I could probably process better now I have more experience).
So don't be afraid to try shorter
Cheers
Rusty