Those are good questions, @edsnova.
The shortest answer I can provide is to say that as important as they are, camshafts are probably the least understood (really truly understood) parts of an internal combustion engine, at least for most of us. It's clear that automotive engineers in manufacturing understand a lot more than hobbyists, because they've been developing variable valve timing strategies for decades. They understand what is happening inside the combustion chamber and are making adjustments accordingly.
A "hot-rodder" (which is what we are, really) is left to extrapolate and experiment. Cams are ground and installed, hoping that they will exhibit the characteristics the builder is aiming for. There are many, many variables that go into the design.
Most of us (and you for sure) understand that the lift and duration determine where the power occurs and how much power is available. But the shape of the lobe, when each valve opens relative to each other (and at what point in the 720* cycle) are very important as well.
The shape of the lobe is why people rave about Web cams. A camshaft lobe can be shaped almost like a box, with very steep opening and closing ramps and a blunt (almost flat) nose-- where peak lift is maintained for most of the intake cycle. This is how roller cam profiles are shaped, and is one of the main advantages of using them. Other cam profiles are shaped more like a splitting wedge, where the opening and closing ramps are slower, but where peak lift is only maintained for a very short period of time. It would seem like getting the valves open as quickly as possible, and keeping them open for as long as possible would be most desirable. There are cams that do that (the FK4X series cams from Engle, etc.). These cams make a lot of power, but they're hard on parts and really noisy. It takes a lot of valve-spring to keep everything in constant contact.
The pushrods in a Type 1 are very, very long, and the rocker arm shafts are really pretty flimsy for what they are being asked to do (2 bolts hold the whole assembly to the head). When you run heavy springs (K650s, etc.), it introduces a lot of stress to the system-- pushrods need to get beefier, rockers need to get a lot stronger, straight-cut cam gears are a necessity to keep the cam from actually being pushed against the thrust bearings by a quieter helical cut gear set. Cam lobes will often go flat. All of the HD parts weigh more and have more inertia when in motion, so it takes ever stronger springs to keep them under control. It's pretty easy for everything to spiral out of control, and the problems all begin with the shape of the cam lobes and how much valvespring it takes to control the moving parts.
So, an ideal lobe has ramps just steep enough to get the valves open quickly with a lot of duration at peak lift. What this looks like is the secret sauce, and everybody has a different answer. Most of the Engle profiles were copied from Detroit V8s back in the 60s-- there hasn't a been a history of sophistication in Type 1 cam profiles. Johannes Persson (JPM) in Sweden has developed his own cams with great lift profiles, which can be used with relatively light springs. The downside is that they cost $700 fob Sweden, which is about 7x what an Engle or CB cam costs. They do include matching lifters, so there's that.
Duration is how long a valve is open, independent of everything else.
From the Summit Racing website (please excuse the klunky prose):
"Advertised Duration is the degrees of crankshaft rotation that the lifter is raised more than a predetermined amount. This predetermined amount varies between manufacturers.
Duration at 0.050" is the degrees of crankshaft rotation between when the lifter is raised 0.050" and when it is 0.050" from its resting position. This is standard among all manufacturers. You should use this value to compare camshafts."
The duration at .050" as compared to advertised duration will give you some idea how aggressive the ramp is on the cam. If the numbers are relatively close, the ramp is relatively steep. If they're not, the lobe profile is less aggressive.
Another thing most guys (me included) don't readily understand is lobe center separation. This is what you were asking about, and this is what was wrong with the Web cam I got from Dan Ruddock. The Lobe Separation Angle determines where the lobes are positioned in relation to one another. Lobe separation determines overlap (how long both the intake and exhaust valves are open at the same time. Generally speaking, narrower lobe separation gives more torque, greater lobe separation gives more upper end horsepower. CB cams are ground on 107* lobe centers (separation angles), Web and most other VW cams are on 108* lobe centers, and LS V8s cams are generally on 112* lobe centers.
The last thing to think about is when the cam opens and closes in relation to the position of the piston. In the drawing above, the cam is "straight up"-- the center of the cam overlap is at TDC, and the distance (in degrees) between TDC and the lobe centerlines is equal. Most cams are ground with some cam advance built in, so that the distance between the lobes in relation to TDC is not the same. This is where adjustable cam gears come into play-- some minor (+/- 4* typically) adjustment is built in so that the cam can be "degreed" to match the cam card (provided with the camshaft) perfectly. This is probably the most important step in blueprinting an engine, and most decent builders will do this even if they do nothing else.
The problem with the Web cam I had was that the lobes were ground on the wrong centerlines. The intake was fine, but the exhaust was 7* late. This would mean that my lobe separation angle was wrong, the overlap was greatly increased, and the cam timing was all wrong. The engine would've run, but not very well. It's a pretty big deal.
I'm not sure if this answered the question, or if it was more like trying to sip from a fire-hose... but with this engine, we've obsessed about a couple of grams of rotating mass, and .2 CC in combustion chamber volume. The camshaft and heads determine the characteristics of the engine. I want the most important single component of the engine to be right.