I had eight were-bitten dwarfs recently. Various injuries from multiple bites to a single through-the-shirt bite. I locked them all in a room, walled it off, and waited.
At the end of the month, none had died of dehydration (all were hungry and thirsty) the dwarf who had the single through-the-shirt bite transformed, as did five of her friends. One of the most heavily injured (and most bitten) didn't transform, he was the first to be killed by the weres. This was unusual: Usually all my dwarfs are infected each from one bite, so the fact that there were some who didn't turn was surprising to me.
When they turned, there was an immediate werebeast-battle where they all killed each other (and the unturned guy with the sword who only had one arm (presumably not his sword arm) killed several before being swamped and killed) and then I had a single definitely were-infected dwarf, slightly injured, in the room, and seven bodies, four of them weres, the rest dwarf. I've still not unwalled it, as that single werebeast is still transforming from dwarf to were, from were to dwarf, on a monthly cycle. He is the winner. He gets to live forever as a were. Lucky him.
I find that at least one bite victim will turn, and infect others. I've never had one die of dehydration or hunger, despite the fact that they have to wait for the month to come around for them to turn. They seem to have at least a 90% chance to turn out to be infected. The weres will then fight, if there's even one who didn't turn, and there will be one successful were who killed all the rest, then if there was anyone else infected, it happens again. If anyone is injured in a werebattle, I wall them all in, as doors don't hold 'em.
Hope this helps.