Few things stress me out more than trying to line up both sides of kapton tape for the Replicator HPB. Doing it by hand always takes me a dozen tries and 20 minutes to get it flat, creaseless, and without overlaps or gaps.
However most jigs i found either weren't printable, or weren't particularly helpful. This little guy is easy to print and easy to use.
Print the jig. May need to be rotated to fit nicely on the build plate.
Unfurl some tape, keeping it lined up with the lip on the long side. Wrap some slack around the short end to maintain some grip.
Then just line up the edges of the jig with the build plate, and press down. now you have a nice straight half of the HPB perfectly taped (helps if you first spritz the bed with windex, to make it easier to push out any bubbles).
Repeat for the other side. As long as you align with the lip on the jig, the two halfs should perfectly line up with no overlap