Time for more experiments. I wanted to see how this idea would work if I put 'spokes' into the corners as well as the sides. Again a little bit of 'tweaking' is needed. In picture one I've added them so that they join to the sides and corners, picture two to 'just' the corners and picture three to the sides only.
I've also changed centre drastically too. I've a feeling this may just work out well in the end.