mutt, on a boeing with autothrottle armed, you don't have to set thrust manually, that is done by the autothrottle system, even if not FADEC-equipped. The autothrottle is clever enough to set the thrust to the correct reduced or full thrust as entered in the fmc (most of the times anyway).
The only thing you have to do is pressing the TO/GA-switch which also does the position update to the runway-threshold.