Hi Don...sounds like you know a bit already. I am still new in the hobby as well...more of a star gazer than an astronomer...have not found any super novas yet
Sounds normal with the filters. Only other thing I have read about filters, is that the app size can effect results. Have you tried heading west...I note you have some forest about 40km near you. Maybe you could try there...although you seem to have some huge light pollution out the the east of you way. Longer focal length and higher mags is what I've read helps with LP, although that me be no good for the targets you intend. Perhaps you could change your strategy and concentrate on bright targets from home, and plan fainter ones for a trip to the blue mountains?
Anyways...best of luck with it...You in a good location if you ever get into Hiking
could always take some Binos on those tracks.
Dave.