Hi Nathan,
A good report mate I enjoyed reading. Probably like most who have replied, I'm more than a little envious. This is probably the most consistently cloudy period I can remember for about 15 years and I'm starting to suffer from photonic deprivation!
I seem to remember discussing the arms in M83 with you a few months back -- I'm glad you saw them. The arms in M51 are probably easier to see than M83 but its low altitude at culmination makes it difficult for us in Australia -- though you in Mt Isa would have it somewhat easier than most of us.
I have seen the arms in M51 from the dark skies of Mudgee in my old 10" in the late 90s (1998 I think) though it was only a few degrees above the horizon at the time. Quite a few of us marvelled at it that night.
Shapley 3 is also a really beautiful object and unlike other ring type nebulae, it may actually be a true torus as opposed to us looking down the axis of a tube -- like M57. And yes, M57 is a stunner and so easy to find.
Even if I'm not seeing the stars, I'm glad someone, somewhere is. Onya!
Best,
Les D