I just threw the students into the lenses lab. I didn't tell them where the screen should go, so it was great to watch students try to figure that out. They were sure it would act like a mirror, and the real image would be on the same side as the object, but once they thought about the difference between reflection and refraction, they weren't so sure. They instinctually went for large F's; I had to cajole them into making small F's. The data came out exactly like it did for concave mirrors, so it was easy to assimilate the new information.
Even without directions, I was impressed most by the wows! I got from the class. Real images are amazing to high school students, even if I find I a bit bored in my expertise. I get joy from their wows. They were, like me, unsurprised that the equations were the same, which I found heartening. I guess they think like physicists, thinking they can use the same model again and again?
I then took eyeglasses and put them in the light of the projector and saw the diverging from (most of) the students' glasses and converging rays from the old person glasses I bought from Target.