I notice you have Rondells like I have and like you I've never been able to get my steering as stable as my other Fords.

When I had mine refurbed last, we tried all 5 wheels on the balancer without tyres and chose the best 4 to fit to the car with the worst as the spare. It did make a difference but it's never been as good as my 120k mile Mondeo is today let alone when it was new.