Getting close now in terms of optimising the parts.
These are just some of the parts tried, several electrolytic caps are not in the shot. The type and brand of cap is making a difference when it comes to reducing the effect of the resonant midrange circuit.
The Tri-Wiring also works better in this respect compared to a single run, quite noticeably better in fact.
Next step will be a new board layout and any final tweaking.