We have a new player, who is introducing a Verditius with an interest in prosthetics. This has all sorts of potential. He has so far been talking about artificial limbs, as you might expect, but I'm sure eyes and more fanciful replacements, or just additions, are in the future.
Problem: I really see little guidance for this sort of thing. I don't recall anything for prothetics, and I've looked where it seems likely. I find nothing in Art & Academy for mundane prothetics. The Mystery of Automata, in HoH: MC, might make a useful basis for artificial limbs.
Probably Sub Rosa, issue #14, p. 14ff, Verditius Longevity Devices. Not a huge fan of that article myself, but it's there. :-/
Does this person want prostethics that are controlled via thought (like natural limbs), or via external commands?
In the former case, Warping will be an issue, since the device has to sense said thoughts, which makes a constant effect, always on InMe effect effectively necessary. Not hard to make, just necessary.
There's a fellow named Timothy Ferguson who has an Ars Magica podcast, and one of the episodes discusses different styles of prosthetic limbs. Mostly non-Verditius styles, sadly for your plans. Listening may give ideas though. Warping is going to be unavoidable I think.
Warping could be avoided if the prosthetic is only used on occasion.
Another thought that might work If you take a less restrictive attitude towards magical sense spells than the rules probably intended, is to give e device a target touch effect that allows it to read the intentions of the wearer. That way the device is the target of the magic rater than the wearer,
As mentioned, I did an article for Sub Rosa describing Verditius prosthetics... Lord knows which name I wrote it under, but it is there if that's of any use. The Sub Rosa reviews thread probably gives a view on the article from a couple of readers.