I have tried several different set of rules each got progressively simpler, I think I've settled on "Six Gun Sound: Blaze of Glory " by Two Hour Wargames.
Some of the other rules tried were "The Rules with No name", "Desperado: I, II & III" (though there is little difference between the three sets.) and "Six Gun Sound"
I used to design scenarios with every player having his own agenda, but they always devolved into every man for himself so that's what we play all the time now, much easier on the old noggin.
All the buildings are scratch built by your humble correspondent (me), Building evolution page
The majority of my figures are Foundry and Old Glory and several figures of unknown manufacturer (possibly Britainna Miniatures and one RAFM or Ral Partha) all are ostensibly 28mm. All painted by me.
Scenario Name (Rules Used)
Robbery in Shinbone. (The Rules with no Name)
Just another day in Shinbone. (The Rules with no Name)
Yet another day in Shinbone (Desperado III)
Jailbreak (Six gun Sound)
Its Mine and I want it Now! (Six Gun Sound)