Could you, in theory, hang a camera off the perspective-tracked plate the way you can with “not Randy’s camera projection”?
I’ve never tried. Always just use the non planar track or go whole hog with a camera track.
EDIT: it works. Make sure that the card hanging off of the tracked axis is zeroed out (don’t try to make it correctly planar). If you do this, and film it through a camera hanging off the card as you would in Randy/Kirk/Patrick’s technique you get a stabilized result that can be successfully re-applied in a downstream action just as you would with a normal camera projection stabilization (copy the action, plug the stabilized output into the card input, remove the diffuse map.)