Toe In is the only adjustment that can be made. Caster and camber are set at the factory.
I use two sections of light pipe that slide into each other. Measure the distance between the tires as high as you can both front and back. There should be 1/16" difference. The front measurement being shorter than the rear.
No experience with the Gunson G4008.
Yes this is good advice; I use a wood beam with right angled extensions that project back parallel to the wheel rims. Measurements then taken in towards the rim edges, front and rear, gives the difference between the front and back, so finding the toe-in. The track rods on my 4/4 at each end have four threads per 5mm, so 1 full rotation of the rod gives 5mm at each end
. And just 1/8th of a turn gives 0.31mm in total.