Rather than build hardware for reach class I like to solder up a protoype board for each lesson. Then I can quickly swap them on the three Arduinos I have. The students can borrow the boards to review without re-building.
The problem is that the diameter of pins and sockets on Arduino is designed to be very firm. I know I will end breaking a board, bending pins or cursing in front of the kids.
Can anyone suggest the diameter of pins to make the shields mate & unmate easily?
Buy lots of these.
Insert them into the Arduino as sacrificial connectors.
If a pin is bent or broken pull off that connector and insert a new one.
Show the students how to pry the shield off with a wooden pry bar etc.