I am the product manager for the DL-860 legalizer and will glady help you resolve this issue. you can email me directly at jeff.witman@harris.com.
The limits that I can recommend are only recommendations. The limits are ussually set by the customer.
RGB limits are
RGB Maximum mV 700
RGB Minimum mV 0
Encoded (composte NTSC
NTSC Setup IRE 7.5
Luma Blk Clip IRE 0.0
Luma Wht Clip IRE 100.0
Composite Lower IRE -20
Composite Upper IRE 120
Chroma Amplitude IRE 120.0