I tried to set one up a couple years ago as a benefit for PF, but could not obtain necessary permitting due to trainer using diamond back rattle snakes which are not permitted to enter Kansas. I went to Amarillo for the class. You might check with JMc in Texas or Bleu in Colorado about those classes.
i looked into this the first time i hunted mt. the general concensus was that the species used for training had to be the same species that the dog would be in contact with while hunting. in fact, there even seemed to be a fair amount of disagreement as to the effectiveness even then.
most humans that are bitten by snakes don't know the snake is there. i would venture a guess that proabably holds true with dogs as well. i'm only speculating here.
i hunt an area with prairie rattlers in early sept. i have not put my dogs through snake avoidance training. i give my dogs the red rock vaccine and we takes our chances.
interesting stat. last year in all of the US, only 5 people were killed by venemous snakes.
again, i only hunt for a week a year in snake country. i would be very interested in hearing other's experience who have far more exposure to snakes than me.