Slip these jigs onto the 3mm stainless steel wire and slide it into the holes where the wire enters the wooden balustrade upright then paint the upright without getting paint on the wire.
Printed with minimal infill in PLA (using the remnants of filament as it doesn't matter what the appearance is like).
I will update the photo when I'm next at the property showing them in place.
update: photo added
Hope this helps others!
The author marked this model as their own original creation.