Tune setting

Is there a way to adjust by a permanent setting the "Tune" power at a fixed level, I would like to have 1 Watt only? My wish is to use this low power when I tune my antenna with a transmatch. I'm using a QDX transmitter, which is very sensible to high SWR with the risk that final BS170 be destroyed when badly tuned. I searched the JTDX manual and found nothing.
73 - Pierre - FK8IH