I put the frame with the glass face down on a flat surface, and then put the negs face up on the glass. If I'm doing more than one neg in the frame, I orient them so that the negs will be partially under half of the spring back that will be clamped down, and partially under the other half, so that I can adjust them when the first half is clamped. Then I put the paper face down on the negs, and then clamp half the back, adjust the negs if necessary, and clamp the other side.

If you plan always to print these negs this way, there's no need to use removable tape. When I gang print four 6x17's as I described above, I just tape the negs together with ordinary Scotch tape, but not to the glass, and trim the excess, but bear in mind that I don't show the rebate in the final print. I trim it off. If you show the rebate, you'll have to test and see if the tape makes a difference.