there is no such thing as a stupid question. if you want to use off the shelf 1156, 1157 modern led motorcycle headlight, flasher and turn signals you need 14.3v or close to it. because the rectifier has a 1.4 v voltage drop the voltage should be 12.9v. and you are good.
have a time limit and cant edit original post. the voltage drop across the bridge is 1.4v. you can wire in 2 diodes in series in the negative voltage regulator wire to cancel out this voltage drop. 12.9 won't charge a battery properly but will run the led's fine.
the bike in the pic the dc voltage is 14.0 (edited)