Frog tape is what painters use for masking. Works much better, can get a crisp line. Something in the tape reacts with the moisture (if I remember correctly) to provide a better seal. It's about 4x the price of masking or green tape. The green and blue tapes are supposed to be easier to remove than masking tape, without pulling paint or paper with them. That is their selling point, not good masking.
And yes, make sure no residue is left behind.
When spray painting with a stencil, use very light coats so there is no liquid buildup on the edge of the stencil. Needs to dry at least to very tacky or dry state before the next coat. Brush painting with a stencil uses very thick paint. So when you compare the application, you can see that any liquid buildup will run between the stencil and the article you are painting due to capillary action.
Tom