P.S if you want all the power from the treats hi & lo power winding's use a three-phase full-wave bridge rectifier circuit in line before your volt reg/rectifier to be safe.
Hell you can even piggy back the lower power windings system with a two-phase full-wave bridge rectifier circuit, have it bypass your new 150 watt regulator.
Just splice it in just before the choke/s.
The lower winding wont overpower anything if you hard wired lights to stay on. (edited)