You are likely to see more posts on this topic on the Tuner/ Tech forum, a couple of clicks over on this site. You could try the Search feature; your query might be specific enough to return some interesting posts.
If you are thinking about doing a big project like this, Tuner/ Tech would be a good place to ask questions, as long as you realize that educating you in-depth about a very serious, though fascinating technical subject like this, is beyond the somewhat more informal and relaxed purpose of the forum (unless you can coax someone to make it the purpose; I confess, I'd love to read the discussion).
Or, if you just want to get pointed in the right direction to learn about how to change (or do a field repair) on a broken string--- including where to order them, how to specify them (gauge, string number, length, wrapped or plain, use of different materials, like stainless steel wire, for special situations), understanding scale design, tensioning, inharmonicity, temperament, the way particular hammers and felts and voicing techniques interact with strings and how things can be manipulated to get around problems--- lots of questions I wouldn't even know how to ask. I cannot even calculate the twelfth root of two; not to save my life.
Who knows, you might be the talented guy to get the very learned rebuilders to talking. Hazards, like overpulling a string past its ability to speak, but not quite to its break point [the smart guys over there know a one-word name for this that I have forgotten; maybe it's as simple as 'dead string'].
It is only too likely that I am revealing my deep ignorance, doing a little reading when I was stealing a little time from playing. The guys who understand this field can tell it right off.
There are some books that you might enjoy. I would suggest having a look over at Piano Technicians Guild website http://ptg.org
in their piano reference book department; you can order these. They have a serious commitment to continuing education for their member piano techs. And, I believe you can order books from the commercial side of this site right here http://pianosupplies.com
and you can always try asking on http://pianobuyer.com
What was it? The modulo of inharmonicity... something about the elastic limit? I'm shaking the brain, but it's not coming out of the ears. Anyway, the last time I suggested, very briefly, where a person with a question might best inquire (right here on PW) I got BLASTED, and reported to the mods. It blew over. But I did say I would try to make more of an effort in the future to be especially nice.
And I wish our OP the best of luck, getting the right answers, from people who really know.