Are rip saws as accurate enough when cutting shoulders?
A rip saw works fine for me on crosscuts. I do like a crosscut saw because it can leave a slightly smoother surface.
This is where filing your own saws can really be helpful. One of my most used saws is filed with just a little fleam. With a lot of old beat up saws to experiment on you can try different rake and fleam combinations to find a few that work best for your students.
It could also be a good subject in class to let the students try the different set ups.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)