Good luck!
I've adjusted the windage on many of my pistols with a brass punch. You can cover the end that strikes the sight with masking tape or a thin cloth-type material for extra protection against scratches. You can also tape up the areas of the slide surrounding the sight so as not to scratch that up either if you accidentally "miss".
Once you're done, if there are small or faint brass marks for any reason, use a metal blue pen, colour over the brass marks until they're gone, and wipe clean.
This is what I do all the time without any issue. But again, that's me...others will certainly have a different approach.
All the best.