Rear carpet on 1969 Dart hardtop, where to cut.

Installing new carpet from stock interiors, the old carpet was thrown away long ago, so I have no template to go by, I have the front installed after trimming excess. what I am trying to figure out is where to cut the rear carpet at the rear. Where the carpet steps up from the bottom of the floor pan to the taller part of the floor where the brackets are that hold in the seat bottom, right not the new carpet covers the brackets, I am trying to figure how close the carpet is supposed to come towards the bracket?

Thanks for the help!