Well Al, that’s what I was thinking of doing with the RFI.  I was just wondering what my argument could be other than faster production.

Many engineers operate under the false assumption that all 70 ksi filler metals meet low hydrogen requirements. We know that isn't the case. When you write the RFI you should list the specific flux core electrode you propose to use and include the brand name. Provide verification the weld deposit meets the low hydrogen requirements as specified by AWS and ASTM for welding the ASTM A992.  One means of accomplishing your goal is to send the EOR a copy of the WPS you intend to use with all the particulars listed.

We know that not all flux cored electrodes are created equal. A sharp engineer would consider other factors beside the ultimate tensile strength of the filler metal when making a decision on which filler metal will provide the optimum properties required meeting anticipated service requirements. Conditions such as static versus cyclic loading, lowest anticipated service temperature and whether there is a concern with notch toughness, the  need to meet low hydrogen requirements, or possibly a chemical match for enhanced resistance to corrosion should be considered when selecting the filler metal. He should compare the published properties of the electrode you propose to use and determine if it meets the service requirements of the project. In this case, with the limited information provided, I don't see why the EOR would reject your proposal provided the low hydrogen requirements are meet.

A simple inquiry should at least provide the EOR with the assurance you respect his opinion and you are not making decisions without his input. It should give him the satisfaction that he is dealing with a professional that understands how the system should work. Should he have an opportunity to work with you in the future he will recall your courtesy and professionalism.

Best regards - Al