Using an clicker eraser and James P. Carse's book "Finite and Infinite Games" to hold the eraser in place in order to manually adjust the backtension on a vhs tape while I digitize it.
Turns out I should have tried a simpler solution first. My TBC was actually making the video worse! Taking the TBC out of the loop got rid of the flagging at the top of the video. Lesson learned! #digipres