The "operating Factor" is going to be dependent upon the weledr, the environment,the electrode, the procedure etc
The operating factor will be better for a 1" in 14" stub loss than 4" in 14" . Slag removal time will vary with position, access etc... Long continious welds will have a higher production factor than stitch welds.
The operating factor would be something you have to study for yourself. I can have a VERY high operating factor depositing 10 lbs of weld metal on a flat butt weld that only has one pass 10 feet long compared to that same 10 lbs that takes 5 passes 2' long.
7024 will have a different amount of time compared to a 7010 or 7018. Even in the same joint.
There is no set operating factor that works for all conditions. I would suggest a time study of your welders. Total Arc Time/Total Work time.