Hi crutschow,
I am almost certain that an SCR will turn off if connected to the putput of a bridge rectifier so long as there is no capacitors on the bridge side of the SCR The current through the SCR will go to zero every half cycle. As the output of the SCR will be connected to a capacitor the current will be zero for quite a large proportion of each half cycle. Putting the SCR on the negative connection to the bridge would make driving it simpler. (But it would probably cause a problem with the half wave control supply.) I think the output from the half wave rectifier would be one half cycle with the peak voltage of the tap to one end of the full Winding (Assuming the full winding was connected to the bridge at the time.) and for the other half cycle the peak voltage from the tap to the other end of the winding. (Ignoring diode forward voltage drops.)