Oooh Heck, Thought it was solved...   I have a C11 which is sometimes difficult to start, and have put the cause down to it wet-sumping.   If left standing for a month, it fills the crankcase and the chaincase from the oil tank.   The additional crankcase pressure. and oil prevents an easy start.   It also has a stupid shock absorber on the primary chain drive, which doesn't help with the kick momentum.

Sorry to hear of the ongoing start problems.  I recently fired up a C15, and my method was as follows...

Tickle until fuel spills from the plunger.
Kick until at the top of the compression stroke, as near tdc as possible, then release the kickstarter to the top.
Twist grip just a bit open... 1/4..
Then Kick down, and continue forward as far as possible, at the bottom of the stroke.

Best of luck, or find a steep hill to bump start it in 3rd or 2nd..

The only problem with tightening the springs too much is that they may bottom out, when you pull in the clutch.  Also it will require more force on the lever, but usually no problem..  The springs need to be matched in tension, so as to lift the friction plates squarely.

The lever on the end of the clutch push-rod should push the rod perpendicular to the rod, for maximum effect, and not be just pushing the rod sideways. The screw and nut at the centre of the clutch plate will allow this adjustment of the clutch rod lever to be made.   
It is all too easy to bottom out any of the adjustment points, which will give you a false feeling at the clutch lever.

Sorry but I can't understand what you want to achieve.   
Do you want the bite point to be 1 inch from the bars (you got small hands..?)..  That would mean you have about 3 inches of slack lever.   The normal amount of slack lever is about 1/4 to 1/2 inch at the lever end.  This is to ensure there is no cable tension when the clutch is engaged.

If the clutch is slipping, can you add some more turns to the spring adjusters..?

As for the clutch plates being worn... you have not worn out the makers name yet..!

I was just looking for some information on local Chrome Platters, and came across a notification that from this year no Chrome parts are allowed on new cars.   This ban is because the chroming process releases very toxic carcenogenic pollutants.
So if you have any parts that could do with re-plating, get it done sooner rather than later, as a total ban on chrome is a possibility.

Sorry to hear of the ongoing problems.  Lots of things you tell us seem to make no sense.
 
For example... The coil case to ground being 10 ohms, is neither grounded nor open circuit, but somewhere in the middle...  Almost like an internal fault to ground, caused by a partial contact to the coil windings.   
I know this won't help much, but my R.E. Bullet coil case is not connected to ground, even though it is clamped to the rear mudguard.!

The other strange thing is that you say the battery voltage sags even with a Battery Charger fitted, and that the lights go dim from just the battery.  Maybe as the voltage is going to 4v, that could suggest only two cells of your battery are good.

Maybe a push down a hill by two strong lads, whilst in second gear, would get it going..  Best of luck..

Unfortunately the 20 inch tyres are very rare these days.  You could visit the dustiest motorcycle shop in your area, he might have one tucked away in the attic...   But even if he does, it might be perished and past its' sell by date.

Many years ago, when I helped with the running of ACU approved events, they produced Indemnity Public Notices, along the lines of...   'Motor racing is dangerous, you are present at this event at your own risk'.   We used to put these Notices up about 50 yards apart, all around the track.   Are you saying this no longer applies..?