I would call that difference in weight negligible and just run them and see if there are any unusual vibrations, if not you're good to go. I've never actually weighed any cutters I've ground and usually they're not exactly the same and one is usually slightly smaller than the other just to make life easier when grinding and have one perfect cutter rather than trying to achieve a perfect two cutter action.
You really only have to worry about balance at the great extremes like trying to set one of these up:
So long as you're not massively out of whack with your cutters, balance shouldn't be too much of an issue.
Always worth standing out of the firing line when you first start it up though, just in case