What I want to see tested is whether or not "stagnant water" causes infection more often than "water" when used to clean dwarves without soap. Or even compare with soap.
I'd suggest getting a few dwarves cut up, make a backup save file, and then try out the various healthcare options to see if it matters. Dwarves have different disease resistances, so you use alternate-reality (save file) versions of themselves as the control group. What kind of time is required for infections to appear after an injury? I've never had any infections with patients at my forts, even when the doctors were lazy.
Do bolts benefit more from having an increased mass or more from having a better cutting edge? (should I focus on silver bolts, or should I make iron bolts?)
I noticed that if bolts cannot penetrate armor, they often still do blunt damage. Bolts have a very small contact area and a high velocity, so they can chip bone through armor like a whip if they don't penetrate. This is very good for disabling, because of the high pain associated with bone injury in the game. However, the target simply won't die unless their skull is fractured into their brain.
I recommend steel, iron, or bronze bolts because they are more likely to penetrate armor and skewer organs. The targets tend to bleed out faster as well. If the targets are unarmored, any bolt will do fine.
Hilariously, adamantine bolts (which have the density of styrofoam) easily penetrate any armor and cause all sorts of nasty internal tearing and bleeding, except for adamantine armor, which they harmlessly deflect off.