I was wondering how the gunfight would play out as a game of Dead Man's Hand and came up with this idea. I suggest that the action takes place around the Livery Stable, the Jail House should be at the opposite end of the street with buildings in between. Although I counted nine riders coming into town the showdown has five baddies near the Livery and three making their way around the backs of the houses, meanwhile the sheriff and three others are hiding in the jail. Having only two heroes up against twelve would not make for much of a game so I suggest one citizen in the Livery with a rifle who will join Charlie and Boss on turn two. Thereafter each other building will have a brave citizen inside, up to five, who will join the fray when two of the baddies are down or either Boss or Charlie becomes a casualty, when they join roll a die to see what they are armed with, 1 a shotgun, 2/3 a repeating rifle, 4/5/6 a pistol. Once the citizens are activated so too are the sheriff and his buddies in the jail. To start the game Charlie has two pistols and a repeating rifle, Boss a shotgun and a pistol, Charlie is the only one who fires on turn one, to repeat his revenge on the gunman Butler he will have one shot with a D20 and he will kill on a 10+, thereafter things will be as normal.
If you play DMH then there are two 'gangs' the citizens and the baddies, Charlie and Boss do not need to take a Big Nerve Test the others do, as for the characters I recommend these :
Boss Spearman- Range Boss
Charlie Waite - 'Man with no name'
Citizens - Citizens, with three being Dudes
Denton Baxter - Boss
Sheriff Poole - Deputy
Butler - Gunslinger (with only two actions due to his broken arm)
Baddies - Dudes, with three being Varmints
To win the baddies have to kill Boss and Charlie, they in turn have to kill Baxter.
I hope to have a chance at playing this in the near future and it may need some refinements but only a play test will tell, meanwhile you can see where I am coming from below -