Set feed rate / speed override to a value at beginning of a job
You can use the M50 and M51 commands at the beginning of a job to set the overrides to certain preferred values. You can, for example, add this in your CAM software as an initial G-Code to set overrides to 100%:
M50 P100 M51 P100
Please note that this will not be effective if you use an analog input to set an override value since the analog input will trigger an update with its analog value.