Having now received some of my own wx images (as per my previous post) I thought it'd be interesting to look at what other people have achieved. I think the following link is a good illustration:
As you can see, I have a long way to go. However, they're using a dedicated receiver and antenna. Plus they have 'Pristine' enhancement turned on, so I might have to read up on that.
Also, another thing I know is that wxtoimg does have support for low S/N signals when you register it, so I wonder if that's at play…
But none the less, when I compare those images to what I achieved, I see the potential. Wow!