I am getting a deeper appreciation of that different papers will need different 'marking' materials.
1) any coated papers ~ Platine, Pearl, Baryta(all of the variants?)..........and of course Gloss and similar high sheen surfaces ~ will need a pigment ink pen.
2) any uncoated papers ~ Matt types................will be OK with any form of pencil, though perhaps a softer 2B or softer might give a look?
In the case my current prints I will have to use a pigment ink pen, arguably a very fine line one. But a thought struck me as one of the criticisms I read to using ink rather than pencil was that and ink writing could be easily copied whereas pencil was harder to copy?
The thought was to use a stylus first to impress the paper and then use the fine line pigment pen to 'fill it in'?
I know I am overthinking this but that is the way my brain works, as in this case pencil poor/unworkable therefore how to make the numbering have a slight uniqueness akin to the advantages of using pencil???