[mickmate]

Good info from Bruce but remember his is a track cornering type set up. He knows more about these suspensions than anyone I've talked to.
Rear toe also is adjustable at the rear lower inner which has much less effect on the other setting like changing radius rod lengths does.
I think Paul my first adjustment for speed stability would be more caster, especially if the steering feels pretty light at low speeds with the radials.
Check the pitch on the threads, use a ratio to make it closer to a true measurement. A good method is adjusting an upper ball joint and simply measuring between pivot points. Translate it into an angle change rather than a distance using a ratio. Best way to do that initially is on an alignment machine and noting the change. Of course that's what you were asking for initially, it's a matter of whether anyone has done this and also remembered it or written it down. When I was racing I had my own code on the decamber plate graduations so no one could read my numbers.