Reasonably simple, but will pass this on if your suspension needs a tweak, and one is so inclined.
A pair of 2 foot levels, 4 nuts of equal height ( ~12mm), a good steel tape, some masking tape .... and a digital level. Tape the nuts to the 2 ft levels so as to create 'stand-offs' that sit at the edge of the rim: the objective is to get the level absolutely parallel to the face of the wheel, avoiding any contact with the tire.
To measure toe in, a helper is needed: the nuts are set to allow the levels to sit parallel to the floor at a height that allows the steel tape to be stretched tight without contacting the underbody. Take measure fore and aft of the tire on the same point on each level, and measure the distance between these 2 points on one level. That distance is the hypoteneuse of a right angle triangle, the height of which is 1/2 the difference in the fore/aft tape measurements. ( the base of this triangle is parallel to the side of the car). Standard trig tables will give the angle of toe in .... or use twice what you calculate for total toe .... piece of cake - and it works !!!!

To measure camber, first you must have a perfectly flat 4 1/2 ft span of floor between the two wheels. A 4 ft level will find that spot, so do the measure there. Position the level and digital gauge vertically as shown in the pic ( there the measure shows as 88.6 deg inboard of 90 deg vertical on the rear wheel, ergo, camber is -1.4 deg. If an adjustment is required, lift the car and remove the wheel: without disturbing the wheel at full droop, remeasure the vertical on the brake disc, and record the number. If, say, another -0.2 deg of camber is reqd, carefully loosen the locknut on the camber eccentric, and dial in the 0.2 .... careful of direction ( ie., more -ve camber means shortening the camber link, etc.). Lock down the counterheld eccentric, refit the wheel, and lower. Roll the car back and forth to release the 'tuck-in', and remeasure. 95% odds will have you at the correct camber first time. These are sensitive adjustments, and non linear, for it is an eccentric after all; however, assume ~0.2 deg ( 0 deg, 12 min.) per division on the eccentric as a starter.)

I've been playing with this, and find that the adjustments are pretty well nuts on ..... just as easy to perfectly center your steering wheel after total toe is correct, etc .

EDIT: I should add - once an eccentrics position is determined, snug down the lock nut just enough to fix it in position: then, jack the hub back up as closely as possible to normal ride height and finish tightening the locknut. This is to avoid damage to the rubber bushing if it is clamped at an extreme angle from normal ride height.

 

Good tips, thanks! One thing I might add, in order to spice up your post you need to change the title to something like " Why four nuts are better than two" or how about "How to make you car handle better by using your nuts."