Which fuel resistor

[Chevy3500]

Ok i need to get a fuel resistor for my pmd. I do alot of towing for my truck but want to get good miliage still so would it be better to have a 5 or 9 resisitor and i read somewhere that the black pmds have to have the green resistors thanks for the help

 

[NVW]

They make virtually no difference. The purpose of the different resistors was to fine tune the IP flow rates.

0-9 might make 2mm3 difference in total fueling.