I have modded a few Toroidal Transformers, the turns per volt works out to about 1.5 to 2 T/volt, if you don't need any regulation for the control circit, a simple bridge is all that is needed.
The Toroid needs to be sized for a suitable Va, for servo calc, they do not draw full power all at the same time.
I just add a single winding per supply with a full wave rectifier.
Al.