1- With one or both A/Ps engaged in CMD, the FCC for the first A/P in CMD is the master FCC, regardless of which F/D is turned on first.
2-Normally, FCC A drives the Captain's command bars and FCC B drives the First Officer's command bars.
Don't get confused between turning on the autopilot and turning on either F/D switch. The best way to not get confused is, as far as possible, have the same selected on both VORs and radial settings.
To think all those 'instant electronics and autoflight experts' in the 737 Turkish AMS thread knew so much better how Boeing should design the complete autoflight/autoland system too!