Rust Again!

At a camera Club Competition the other night I was given a really low mark for a rust image.  I was disappointed but, as I respect that particular judge, I accepted the criticism which was 'too bright' (fair enough as taken in bright sunlight and I could have controlled that better) and focus was 'not pin-sharp'.  It was but not all over.

This morning I returned to the rust and took great care to control light better with a much smaller f-stop and positioning of camera.  I was using a 105mm macro lens but still, whilst a lot of it is as sharp as it can be, the whole area is not absolutely sharp.

So where do I go from here?  
a) Use a different lens?  
b) Focus stack?  
c) Give up this Rust idea as a theme for an A panel as it's too tricky?
d) throw the camera in the bin?

Any advice welcome.