Which type characters do you prefer?
Traditional centered, simplified small 漢汉
Simplified centered, traditional small 汉漢

I personally print them on 120 gram yellow A4 paper, which can be bought in most office supply stores. 160 gram paper is better, but my printer cannot load them from the paper tray and cutting the cards takes more time.

The cards are constructed in a way that it does not matter if the alignment between front and back side is a few millimeters off and the number of cuts is minimimized. I use a paper cutter comparable to this one.

NOTE: If you select too many cards at once, generating the PDF might fail. If this happens, select fewer card sets and try again. 600 cards at a time should be fine.