What does c. f. bottom mean?
Max, cf. means compared with. Sorry, old habits! I've always used c.f. but it's really cf., so corrected on that one!
cf. is an abbreviation for the Latin-derived (but also modern English) word confer, meaning "compare" or "consult". It is mainly used in common and statute law contexts as well as in academic writing.
=====Now, a few things...=========================
That Wiki article was just me stating what these things mean. As above with camber, it's not obvious what the sign convention is i.e. which way things go when +ve or -ve. And of course it matters, a lot!
The Brickyard has all the setting figures. (There has been some confusion by VW over the years about correct Syncro settings, information appears on the Syncronauts Website from various sources. Some mfrs of alignment equipment even programmed in the wrong figures)
On cost and quality... Bearing in mind what we find with some garages today, and esp. quality of staff in some tyre-centres, I might be happy to have all the settings checked and reported by an alignment service, but would be pretty circumspect about allowing them to re-set anything... Unfortunately, they are not always of like mind and seem to want to dive at everything with spanners & hammers before sucking their teeth quite enough for my liking (e.g. a few minutes of error in a setting angle, is better than loosening a wickedly corroded bolt around a wickedly naff bush and re-setting it wickedly wrong!) Just my take, I may be getting cynical in my old age...
The normal setting home mechanics do themselves would be
toe-in (or out), and even then takes a fair time to get it right, as needs to be done (or checked) 2 or 3 times rolling vehicle back and forth between checks. One reason is wheel rim deformation, another is any play in rack or tie-rod ends. Also, it used to be quite common to find the rack has been de-centred when doing toe-in amateurishly, by not adjusting both tie-rods and it does matter if it's well out (gives bump steer). Fortunately, unless the steering box splines have been off, T25 steering wheels and racks are very accurately centred and will be noticed.
2WDs have very slight toe-in, Syncros parallel to slight toe-out (but dependent upon ride-height). Toe affects steering sensitivity to knocks and bumps (whitelining) and 'turn-in' and works with caster for straight-line stability.
Camber generally not done at home, but I like the kit MaxStu*
Camber is dependent on ride-height. Rolling about back & forth and re-checking is also recommended for camber.
Waste of time if the top or bottom wishbone bushes are knackered or a ball-joint has play in it. If the eccentric pin doesn't look central in the top bush, that's a clue.
Camber is nominally 0 degrees, each wheel to be within 1 degree of the other. Slight +ve camber on Syncros.
Camber affects the oversteer/understeer, load/temp across the tyre width and ultimate cornering forces more than any other parameter.
As the wheels are turned, +ve caster creates negative camber on the outside wheel,
Caster (Castor is oil from the castor bean, you remember Castrol 'R'
)
This is set by the forward radius rods, sometimes called tie-rods so if those big rubber bushes at the front have had it, and the sleeve inside is rotten to the core, then caster will be changing a bit as you brake and accelerate and negotaite corners, much as camber will with a badly worn wishbone bush or ball-joint.
Caster affects straight-line stability and steering weight, as well as changing camber angle as the wheels are turned, increasing neggy camber on the outside wheel with tighter turn radius, a +ve effect.
Critical point here is that they are the same (provided the thing hasn't been badly bent, when it may well require them to measure differently to drive straight and true, ditto camber; until its been straightened!)
Recent discussion about changing these bushes in Tech, getting the sleeves made up (now NLA apparently from VW Spares)... at least, accurately mark the rear backing nut on the rod, before moving it, this is what sets the position & hence caster angle.
b]With rear-wheel drive vehicles it is extremely important that the rear toe and camber angles are checked as well. The toe especially![/b]
Notes:
These settings are not just about tyre wear, they affect steering as well as handling characteristics and they interact to an extent.
These are 'static' but change dynamically with load, load distribution, roll, cornering forces and acceleration and braking. The dynamic changes are set 'by design' and also affected bush compliance.
With independent suspension rear-wheel drive vehicles it is important that the rear toe and camber angles are checked as well. The toe-in especially, as toe-out can cause instability! T25s have very slight toe-in (10'), but the +/- tolerances allow a smidge of toe-out.
NB. If using setting gaps rather than angles, then wheel size will affect the measurement.
Always tighten suspension bolts up with WoW (weight on wheels), esp. rubber jointed ones like top and bottom inner wishbones and shock absorber bolts; a 2nd lightweight trolley jack comes in handy at times like this.
T25s are very robust IMHO, it always amazes even some of the Synro die-hards that after a thorough battering of the worst kind, they can have their tyre pressures checked/reset and then be driven on tarmac again without pulling or behaving erratically nor requiring much attention thereafter. There are of course things that wear out quicker or do sometimes get damaged, but overall, they are very resistant to being seriously damaged or misaligned in the suspension department.
Further reading links:
More about alignment and their effects
Everything you ever wanted to know about tyres (hopefully!)
More on alignment and vehicle stability (or not!)l
=============
*MaxStu, if you cut a chunk out of your wedge of wood, it will fit right over the bearing-cap, allowing its use at the wheel centreline and a bit more accuracy. I suppose in Scandinavia they wait until the local lake freezes over and use that as a perfectly true horizontal surface!
For the home mechanic, toe-in can more accurately be measured using a variation on your plank idea. The longer the better but must be dead true, and have a chunk cutout for the bearing cap... then prop them at wheel centre height both at the wheel and far in-front of vehicle and some calculations will indicate the toe angle (we could easily create a table of measurements against angles for a couple of distances in-front of the wheel) - much better than that awful '
string' method, which I've never got on with myself much.
. 
) and NO unusual excess or strange tyre wear.
used to draw a line around tread of tire on center... Jack up wheel and spin it while a nail sticking through a board rubs on tread... leave a nice fine line around tire tread. Do this on both tires and measure distance.. Also roll van back 5 or 6 feet and then back forward after adjusting before measuring to settle suspension after changes.
