The stretched paper after it has dried. It does buckle some after I add the staples. It could be that I am too impatient to wait long enough for full stretching, but the paper dries very flat and tight and stays mostly flat when I work. If it buckles a little I ignore it.
I add the tape on stretched paper for classes or workshops because traveling often causes the staples to come out. If the paper is staying home I do not add the tape. I don't add the tape until the paper is dry. When I remove the tape at the end I remove it when the paper is dry and I remove/peel it slowly so I don't damage the paper. I use 1" painter's tape (unless I am out and only have wider tape which happens)