Which one and why?

As for which seal to use, rubber or rope. I would look close at the seal area of the crank shaft. If there is heavy knurling on there use the rope seal. If it is smooth, use the rubber seal.
Charlie, when I rebuilt the OE slant from the 68 Barracuda, I looked closely at the knurling and how it matched to a new style rubber lip seal. The lip seal ran close to the knurled finish at the rear main but did not run on it. I used a rubber lip seal. That motor originally had a rope seal. And I used the OE ‘68 rear seal career.