Leica IIIc horizontal rangefinder alignment question

[PFGS]

I understand that the horizontal adjustment is under the cover screw to the side of the front finder window. When I take off that screw, I see a brass circle with a slot cut across it & a hole with the threads that held the cover screw. And deep down in that hole, I think I see a tiny slotted screw - that screw is the alignment adjuster, yes? Not turning the outer brass via the slots? If so, can someone recommend (ideally via a retailer link) a screwdriver that can reach that screw? My present set of jeweler's screwdrivers sufficed to fix the shutter, but none are small enough to fit in that hole.

 

[Granite Rose Studio]

You will require a 1.0mm wide screwdriver to perform the adjustment.

 

[bdial]

https://www.kctoolco.com/screwdrivers/?_bc_fsnf=1&Tipsize=Slotted+1.0+mm+(.039+in.)