[Jim Huseby]

Don't take me wrong (and I know you have already heavily reflected on this), but with less time and effort than you've already expended, you could have removed the front axle assembly including brakes, spring and wishbone and done a precision rebuild of every little component. With the excellent and extensive advice you've gotten on this thread, you could now do a superb and comprehensive job. Your A deserves this, and so does your driving experience. IMO, the A was a finely built machine and when carefully and properly restored to specs there is just nothing like the driving pleasure. IMO having an A "adequate" is not the same as "excellent". Two different worlds, and you should be enjoying the "excellent".
Too much caster has been mentioned as a contributing factor and can be measured on the car with the plumbob method or an angle finder. Do this with the size tires, tire pressures and spring heights you're going to run. If the front spring is de-arched too much that will increase caster. Frame sag, normally concentrated near the rear motor mount and front body mount area, will also increase caster a slight amount. Look at your gap between the front body mounts and frame and your hood fit for indications of frame sag, sideways bending or diamonding. It is easy to measure the axle on the bench for bends and twists and should be done while it is out of the car. There was a recent thread about axles. Also, look for a crack or break on the radius rods where they attach to the axle. While you have the spring out, clean the heck out of the front crossmember top and bottom to inspect for cracks there. There is an easy way to make a close guess on frame twist and spring lopsidedness with a floor jack. Thanks for getting this interesting thread started.