Yep, typing paper, craft paper, thin gasket material, all will work. It is also a good idea to measure squish above each end of the wrist pin. I use #7 lead shot out of a shotgun shell for this. I position the 2 pieces of shot on the piston above each end of the wrist pin, as close to the edge as I can. I make sure I am not under a valve and I keep the shot in place with a little dab of grease to insure it dosn't roll around. SInce the shot starts at a uniform shape/thickness, it presses out into a neat little easy to measure pancake. The reason to measure at each end of the wrist pin is to insure the cylinder bore is perpendicular to the crank. This alignment is the sum of a lot of things such as the machining of the crankshaft main bearing carriers in relation to the block deck that the cylinder sets on, the cylinder case itself and the bore in the cylinder that the cylinder liner sets in. IF all the machinework dosn't line up correctly, it will show as differential squish across the piston top. if you get differential squish, that measn the piston is most likley traveling back and forth on the wrist pin. If it is bad enough, it will run out of travel at the extreme top and bottom and can cause the piston to touch/scuff the cylinders. It can also cause abnormal ring wear.
The real fix is to properly machine all these parts to get the final piston alignment in the bore correct. Or do what the indians do and use shims under one half of the cylinder or the other untill the difference in squish across the top of the piston is 0. Many listeroids have half gasket shims and I believe the indians use differential squish to determine what size half gasket to use to get the cylinder bore perpendicular to the crankshaft. The mis-alignment was quite large on my 6/1. I opted to fix the mis-aligned crankshaft bearing carriers to bring it in line rather than use half gaskets...