Bryon, the A693 (I think that was with drawn a few years ago) is Zink coated sheet metal best I can figure. I doubt you intend to PWHT. Not knowing the application.....My thoughts would be turn to
INCO A (ENiCrFe-2)(SAW),
INCO 182 (ENiCrFe-3)(SAW),
or INCO 82 (ENiCr-3)(GTAW). You don't need to buy INCO (pretty pricey) but like American filler metals brand works as well.
The SS you mention is a PH material, didn’t know if you were aware of that, you will loose that quality at the weld.
Again not knowing the application, I will just throw in that you can Butter the SS side with 630 before making the joint, just a thought.