I've used a simple wooden frame, a similar principle to Harry above, for over 40 years.
One length fits across and under the car. At each end us dovetailed a vertical length of wood with holes drilled for various wheel diameters.
Initially I used two five inch nails, but one works well enough.
So first, I place the frame in front of the wheels, and adjust the nail so that it just touches the rim (3 o'clock nearside in this example).
Next, I measure, using a metal tape, the gap between the frame on the offside, and the wheel rim at 9 o'clock.
Repeat with the frame behind the wheels. Compare the measurements. For toe in, the front measurement needs to be more than the rear, by the amount of toe in. Because I measure from the outside.
I've never had a problem using this method.
Would love to see a picture of this in action Dave 😁
