Snap caps for a rimfire are money wasted. The rim gets beat to heck in short order, if the material is soft enough to not damage the firing pin, and they cease to work. Snap caps for CF usually have a rubber or spring loaded section that will withstand the repeated strikes.
You can use fired cases if you really feel the need.
Most of what I have seen on the store racks have been action proving dummy rounds, and they say not to drop the pin on them or they will be damaged.
If you use the paper method, you are looking for any mark on the paper that would indicate the pin is able to strike the edge of the chamber. Bad thing to have a mark.
FWIW, the Ruger semi auto .22 pistol will assemble and function just fine without the cross pin through the bolt (it can fall free on the bench) and the pin is responsible for stopping the firing pin from getting far enough forward to reach the chamber.
Learned that one the hard way. DoH!!!
Cheers
Trev