wrinkledoggi - I'm not sure where to start.
Don't use the cable sheath adjuster to adjust your slide level for idle - a big no-no. Besides other considerations, this leaves no slack in the cable, so when you corner, your idle is likely to increase.
The idle speed screw is there for setting the idle speed.
The cable should have 2-3mm free play so that as you move the handlebars from side to side the cable doesn't tighten and open the throttle further than intended. (Can be great fun when doing a u-turn.)
Also, once the engine is running, you don't necessarily need to pedal before releasing the clutch - depends on bodyweight etc. If you can take off without pedalling, go for it.
moving the C-clip on the needle inside the carb to change the "length" of the cable by mm
The purpose of the 'C' clip is
not to change the length of the cable by mm.
The purpose of the 'C' clip is to make the (low to mid-range RPM) mixture richer or leaner by varying the amount of fuel relative to the amount of air passing the slide. ie. Raising the needle by one notch adds more fuel to the mix for a given slide opening.
With the clutch shudder, it's
possible that the problem is being caused by poor clutch adjustment, as suggested by happycheapskate, so check to see that it's engaging properly and that there is some free play in the clutch cable when the clutch is engaged.
I would also check under the RHS side-cover and ensure that everything is tight.
These things
do vibrate quite a bit until the clutch is fully disengaged and you get up to speed. Riding too slowly, near walking speed, will labour the engine and cause some shuddering and chain snatch etc. They're a bit lumpy until they get rolling properly.
... Steve