There was also a book by des hamill that wasn't bad if I recall (I had it at one stage but gave it to a bloke that got a dellorto off me for his mini).
What I would say is this though - whilst there is no doubt that if you are going to run carbs, then the webers are without equal - it's not necessarily the best choice here.
Webers will not (usually) make the same peak hp as a large plenum single carb setup (though to be fair I don't know of any off the shelf intakes that would actually truly fit into that category, so this is a theoretical discussion). But what the _do_ do is have the widest powerband (it'll 'come up on' the cam - even on a wild cam, a fair few hundred rpm sooner than a large single carb setup, and tend to 'hold on' longer in each gear) - so whilst it is very very marginally down on peak power, it has far better throttle response, and wider powerband, and on any racetrack, with the possible exception of something like Bathurst, with huge long straights, the webers are just unmatchable by any other carb setup.
That's where it stands for racing. But I would strongly remind that for a streeter, you aren't 'tied down' by regulations, or capacity limits, nor do you have an unlimited budget. And that's where the webers start to have some issues. Namely this - a highly developed webered a12 (factoring in the costs of proper carb optimisation, either on a dyno, or with 'mobile' exhaust gas analyser - and the latter has the advantage that you see what it does on the road, with air being shunted in through the radiator etc, which isn't quite the same - close but not quite - as on a dyno even with a big fan at the front) - anyway that highly developed a12 will still get snotted by a relatively more modestly modified a15, with good but not 'ultimate' carburettion (perhaps a set of twin SUs for example). The a15 won't have to rev as hard to make the same horsepower, and will have far more mid range torque, and will 'work' with a more street friendly diff ratio that doesn't have it screaming just doing runs here and there on a highway. WIth the same cam (and you wouldn't necessarily have to run the same cam) the a12 will have a much worse idle, and low rpm output. THe larger motors really 'tame' the cam and make it far more streetable.
As a very rough guideline - if you made 110bhp with an a12 (and 110 is just a random number, I could have said 100, or whatever) and it made that 110 at 7000rpm (which would probably tie in with you shifting gears at around 7600-7900 or thereabouts) - well with the same general buildup of an a15, it'd make that 110bhp at around 5500rpm, and be upshifting at 6000-6200 roughly.
That's a hell of a difference in rpm and that translates into longer engine life (though admittedly, if they were at the same rpms, the a12 will outlive an a15). And as mentioned, if the a12 made that 110bhp, it'd probably make about 120 ftlbs of torque (at some other rpm) and the a15 would likely make 150 or so ft lbs of torque.
I guess what I'm saying is that I have massive respect for webers, but if I was in your shoes, I'd much prefer spending the money on an a15 based combo, with less exotic carbs, for a better overall result.
Of course if price isn't a big deal, you could just as easily run a good set of webers on a highly modified a15, and that'd be one hell of a weapon.
On exhaust gas analysers - I don't own one, but if I was going to get one - my pick would be (partly based on locatin) the tech edge WBO2 gear
http://wbo2.com/ - reasonable enough price, good track record, the ability to log (either in real time, or to later download to a laptop or whatever) and they also take other inputs for the logging, so you can log it with rpm, and (iirc) there's a couple of spares, so you could log manifold vac or throttle position or whatever). There is freeware available to view/compare logs/charts - so not a bad option at all. That's not to say there aren't other products out there just as good, but I know of a hell of a lot of people with tech edge gear, and all happy with it.
There's also one by innovate - I think US based, but don't quote me on that. Whilst I haven't used their product, I do recall they had user forums, and some of the best carb related setup info is there, or was, last I looked, a few years back,. They were one of the few places that delved into emulsion tube setup, both for webers and for big single carb stuff like Holleys (where the 'tube' is actually built into the metering block) and the differences between them and why they behave so differently (the short reason is because webers see one individual cylinder pulsed intake flow, whereas the holleys see a more 'smoothed out' constant flow drawing from all cylinders with sizeable overlap of each pulse.
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