Quote: "I do think I'll take your advice and get some springs and screws. These, along with a few firing pins and some trigger/hammer parts, ought to be enough. Maybe an extra cylinder, too."
If you must spend extra money, then springs, screws are fine. In 47 years of shooting S&W revolvers I have never broken a firing pin, trigger, hammer, nor lost a screw. I have replaced main springs and trigger return springs to improve/lighten DA trigger pull and put Herrett's Jordan Trooper custom grips on them. Cylinders must be fitted to each gun by gunsmith. Don't know if S&W sells them to non-gunsmiths or not. I would spend the money on an extra pistol. YMMV.
Good shooting and be safe.