Bob, if it is a class that hasn't done lith before, Fomatone is hard to beat. It is very easy to control and get good results with a wide range of exposures and agitation schemes. Fomabrom is a really interesting paper that I find it takes more effort (and pieces of paper!) to get what I want. I've never used the RC version of Fomatone so I don't know how that works. I've attached a couple of untoned examples to try to show the range of tones you can get.