
I'll go back and reread the entire thread, but in the meantime, can you adjust your idle speed temporarily so that it's quite a bit higher? Maybe 1500 rpm instead of the nominal 850? I know the engine won't like this, but see if you still have the stalling problem when stopping or turning, with an artificially "boosted" idle speed.
I vaguely recall a Fiat I had many moons ago that had a very low idle that seemed OK when the car was just sitting there, but if you put any extra load on the engine like from the brake lights (load on the alternator) to shifting fuel levels in the carb float bowl, and the engine would stall. The solution was just to turn up the idle speed a bit.
-Bryan