You don't want to weld galvanized steel without first removing all the galvanize in the area of the weld and adjacent surfaces.

Once the joint is properly prepared, I would expect acceptable results with any filler metal / base metal combination that can meet Charpy Impact requirements.

What welding process are you proposing to use? What is the base metal material specification? The weld joint can not be expected to pass if both the filler metal and the base metal specifications don't include impact requirements.