I'm not sure I can give a full technical explanation (need Barry Lane to do that), but the critical thing in starting a 331 engine is that the props not slip off the start locks. So, if you were to have the power lever too far back, as oil pressure starts to come up, it is possible to cause that to happen.
Starting at flight idle is always safe from that perspective, with either Bendix or Woodward.
However, the difference between Bendix and Woodward is that at flight idle on the ground, with the condition levers in LOW RPM, the Bendix will be at about 65% and the Woodward will be at about 90%. So if you start a Woodward at flight idle (which is perfectly fine), you have to remember to pull it back as it goes through 65-70%, or it will go up to 90% and make a bunch of noise.
Does that answer your question?