@Williarob Wow thanks for the information! I’ll definitely check out the videos and try to get that batch processor running. Your suggestion concerning AfterFX is similar to what I use within Nuke; I set up the two sources, insert a grid align on the HDTV source, merge the two sources via a Plate_Align gizmo (it works a LOT better than difference mode to my eye), and tweak the grid points until it gets close enough.
Processing via photoshop would at least result in me having to manually correct my grid transform node less frequently.
Oi, all this work to fix some idiocy on the part of a colorist.