All of what Roscoe Coles and St. George said above, plus...
First that is pretty nifty, portraying the Californiano culture. I'd love to do it but not a big call for it in Michigan
I am not clear on who you are. Maybe you have not decided yet. Are you an Anglo or Hispanic? Are you a land owner or a Vaquero?
Remember the period if your year is 1860 or thereabout. Anglo's and the Hispanic culture were not mixing well. Anglo's were grabbing land, business and the political structure, Hispanic property owners were losing out. Neither one was a Vaquero. You can portray a Vaquero, but that would have been a poor cow herder many times Indian or of mixed blood. The Gentry were not Vaquero's for the most part. Think Charro if you are portraying the Gentry.
If you are portraying a Anglo look to what was being worn back east. If you are portraying a Hispanic look not to what the average Mexican was wearing, but to what the more pure blooded Spaniard in Mexico was wearing or if you can find them pictures of Californios - they exist in common books we all look at but they are few.
As you probably are aware, there is a profound difference between the cattle culture of Texas and and what eventually evolved into the "buckaroo" culture. Saddles, roping technique, ropes, dress, horsemanship, spurs, etc. If you are going to represent this to the public you need to know it all.
I suggest you start by doing some reading before you step into an instructors role, and I believe a good place to start is by purchasing David Dary's
Cowboy Culture, University of Kansas Press. Start with page 44, the Californio culture. But then read the entire book so that you can articulate the difference. It is fascinating.
Once you know, what it is you are portraying - look for images from about the same time and look like them. I'd stay away from the traditional SASS suppliers and the Wah Maker stuff, good for that crowd but not reenacting. There are other sources, but most importantly you can make your own with some effort and that will give a superior result.
Ah yes, the guns. I think we have had this discussion elsewhere. I got it. You already have Rugers. And you are right, many probably can't tell the difference. The same could probably be said if you carried a S&W military and police (not being mean, that is just the way it is with the public). However, you know it and I guarantee there will be a few others that do and that will form in their mind what they think about the rest of what you are telling them - if they stick around to listen. Ask yourself, do I even need to carry a weapon in 1860 for what I am doing? Unless you are Joaquin Marietta, perhaps not. There is so much more to history than a few shoot-outs you may not need them. I guarantee that a roping exhibition with a reatta would impress me alot more about your knowledge base than a few gun shots.
But if guns are a must..., I get the fact that at a great distance a Ruger might be confused with a Rem NMA. But you put your year at 1860. There were very, very few old models, transition models, or NMA's available at all in that year (it is my opinion that the public in the far west did not have great access to them until after the war). Despite the repro reference to 1858 the repro mimics a gun that wasn't around until 1863 or so. Consider what others have said above, I have seen pictures of Californio's from your time period with Dragoons, 1851 Colts and pepperboxes - but I can not recall one from that period using a Rem NMA. Really consider the use of your Rugers before approaching the public. If you need to do a shoot out put them on for that, consider not wearing them other than that.
And that brings up holsters...., Will Gromley makes some cool looking stuff for sure (whatever you do don't get any of the nickel spotted stuff). But please consider Old West Reproductions. Most cowboy holster guy's use leather that does not seem to mimic what was used during the period. Rick Bachman seems to get it right. A floral slim jim straight hang holster (forget the canted stuff, I have only one reference for one of those and it was made by a military saddler) on the off side would be dandy for the gentry. A poor vaquero would have probably worn a simple leather contraption at his side (something you can make) or stuck the gun in a sash or his pants.
Meant no harm - hope nothing has offended you. But many of us on these boards feel we have a deep responsibility to get it right when addressing the public. If I did you any favors - get that book by Dary!!!!