PT6 Ops
IIRC having the ice vanes open reduces the engine power (14%on a C90A with -21 engines) so i cant see a advantage to having them open for take-off unless conditions such as freezing fog and snow covered runways. As for the windscreen heat keeping the glass above 0 degrees would probably reduce the chance of the screen shattering on impact. The only thing a can say is make sure you only turn the prop and windscreen heat on after take off .
414AC