Ackerman help
 

This Ackerman measurement from the kingpin is all very well, but nobody can advise me whether I should be running the string from the top of the kingpin, the bottom or the middle. Consider kingpin inclination. Your ideas, guys

I wouldn't over think it too much. Get it close and call it good. Look at the Chevy Blazer and Suburban as an example. Huge difference in wheelbase, yet they use the exact same spindels and steering arms. The akerman cant be exact on both.

Unless you changed the length of the pittman arm or the idler arm the ackerman angle will be what it was when the car left the factory. To measure it you just need to be parralell to the wheel on both sides with a perpendicualer reference line in front of the vehichle to provide an intersection for measurement .measure each side when turned left or right.
2 cheap lasers would be the way to check it. Mount one on each wheel, keeping them level or horizontal ( not totally critical either). Most important would be to keep them parallel with the wheel

I agree with the above. Don't over think the Ackerman. If you watch a Ford F100 pull into a parking spot the front wheels will squall the Ackerman is so far off. Did you ever have a parts man ask if a front suspension part was for a short or long wheelbase? Consider that the Ackerman only applies when the wheels are turned sharply. That is not much of the time or much of the distance those tires are going to roll. IMHO

John L

akerman angle
 

My brother used to race go karts. the ones with the wrong geometry would slow down in the corners, The akerman problems shows up when someone reverses spindles and puts the tie rod opposite of what they were designed . you see quite a few on T buckets built wrong. tie rod out in front of the axle with spindles designed for rear tierods. on a smooth road wrong akerman will just scrub off the tires, on a bumpy road in a turn the car can dart to which ever side has the best road contact.

Run the string horizontal at steering outer ball joint height to where it crosses a direct line between upper and lower ball joints (the steering axis).

But like others here have already said, unless you are mixing parts or doing something really radical, whatever the factory put into it is probably fine.

Of all the suspension geometry possibilities, Ackerman is probably the least important of all.