That piece of paper trick should be tossed in the circular file labeled "things that sort of work sometimes" or put in the file "when accuracy is really not all that important".
I started out that way. Then I moved on to using a small piece of square aluminum bar stock .5 X .5 X 3 inches long. Used it like a feeler gage. Worked better than the paper. But it is still not as good as using a puck or other piece of flat material wired into the machine. That is what I do these days.
I still use the square aluminum bar to find edges.
You will think that you have died and gone to heaven when you start using a puck to set depth. Things just come out perfect every time depth wise. And none of that "jog a thou, feel, jog, feel, jog, feel, oops, start over stuff"
Low Profile CNC Router Vise