Is it possible to image faint OIII objects from light polluted skies like Bortle 8/9 city sky?

This is an enormous amount of time (relatively though, due to British weather) spent on narrowband imaging of Ou4 (Squid nebula) from my backyard.
This data is complimented by LRGB images both from my backyard, and from relatively dark skies location Bortle 4. I was not able to get any Oxygen data from the dark sky location, only LRGB information.

I spend over 60 hours in different attempts to process this image, and every time the verdict was 'I need more data'. As the target settles quite early now, and it is impossible for me to gather enough of effective photons from the Ou4 itself, rather than the sky gradient of approximately 30-50º altitude, I decided to conclude this image for this year.

Being the first target imaged in mono for myself, and being challenging target itself, Ou4 is extremely faint OIII object of uncertain origin (yes, still uncertain, and it was discovered only about 10 years ago, 2011 to be precise). Do I love challenges? Oh yes, just take a look at my previous targets/projects. It looks like I've got the slogan "this is a hobby of a lifetime" too literally, as my projects tend to last more than a year. 

I think, this target worth revisiting the following year. And with proper planning, I should start imaging earlier in the year, and supposedly, visit dark sky locations as well as pay integration time efforts from my Bortle 8/9 backyard.

Getting back to the headline of this image:
Oh yes, it is possible to image faint objects.
Oh yes, it is hard.


Acquisition:

@Gleb Deykalo – gathering LRGB photons from Bortle 4 location with his EvoGuide 50 and QHY294M Pro camera in two panels mosaic
@Konstantin Dzuin – gathering LRGB photons from Bortle 8/9 location with his RedCat51 and ASI2600MM Pro camera in a single panel, as well as narrowband data for Hydrogen Alpha (Ha) and Doubly Ionized Oxygen (OIII)


Processing:

@Gleb Deykalo – inspiration for LRGB look, feedback on Oxygen data ('stretch it more')
@Konstantin Dzuin – processing of LRGB and narrowband data, blending LRGB, Ha and OIII data


Close ups:

Dark Seahorse Nebula (Barnard 150, LDN 1082)
This nebula is a dark molecular cloud of dust, that doesn't emit or reflect light, but rather blocks it from reaching the viewer, creating this dark spots in the image. Though, some stars are rendered in the front of the cloud, and some are barely visible from the clouds themselves. 


Flying Bat and Squid Nebulae (Sh2-129, Ou4)
Sh2-129 is rendered in both LRGB and Ha and it is rich in red from Hydrogen Alpha (Ha, 656.3nm).
Ou4 is recently (2011) discovered object rendered in blue-green of Doubly Ionized Oxygen (OIII, 500.7nm)