I think that's a great effort of what I've found to be a relatively hard object to image. NGC300 is often either too big or too small for telescope FOV's, and quite faint overall.
Sure more exposure time would always help but 4.75 hours can be hard to find as it is
And your result looks good for the amount of exposure time.
The contrast of colours you've achieved looks good but I'm tempted to darken the background more and it looks like you need a flat frame in your reduction, as the bottom of the frame is brighter than the top of the frame, or perhaps there's a light gradient for some other reason, which could be corrected in processing.
