> Conclusion - still unclear what the full throttle switch is intended to do
> : advance the curve, richen the mixture or a combination; believe that is
> not crucial but nevertheless a problem.

Gawd, I'm on a roll!  The function of the full-throttle switch is to 
enrichen the mixture at full throttle-- to provide more power (ha!).  
It doesn't affect (or is it effect?) anything else.  By not using the 
switch, you won't gain that last bit of power resulting from an 
enrichened mixture.  READ:  with as underpowered as we all are, it 
won't be perceptable.

The idle switch is more critical for idle/low speed smoothness.  
Don't blow this one off in the adjustments/tune-up.