I made a crucifixion movie for our CruxWinds group in Second Life using three members as victims (2 males, 1 female) and then went about finding three sets of screaming sounds via Google. I spent countless hours, days, even weeks trying to fit the sounds to the nailing and crucifixion timeline of the three victims. That was one hell of a job and it ended up as a real disaster!
As you move the nailing from victim to victim, the previous one(s) is still screaming. In the end I had 4 separate sound tracks, one each for the three victims screaming and one other for the hammer/nail sounds and the crowd. It was terrible to listen to, but pretty good movie if you turned off the sound.
It did make me wonder just what a real crucifixion scene would sound like. It would be very loud screaming, screaming, screaming which after about 5 seconds is very annoying to listen too. I doubt very much if one could hear over the screams of the victims the insults and mockery from the crowd, much less words between the victims about meeting up in paradise. Guess you can't just drive nails through people without creating some sort of fuss.
Probably best to have a bit of screaming during the nailing and then some moans and groans as they hang crucified.