We're kind of going off the deep end. We don't know what the applications, what code applies, and a lot of other details.I think I said it before, I would pick a filler metal that meets the requirements, rather than reinventing the wheel.
When toughness is a requirement, I limit the WPS to specification, classification, masnufacturer, and brand name. The original post just asked if the electrode classification could be used at lower temperature and could it meet toughness requirements. We don't even know what the toughness requirement is at this point.