Pulling the plenum (upper manifold) is just difficult enough to make you feel like you really accomplished something, and makes servicing much easier in the future. Doing the coolant bypass is a no brainer while the plenum is off, and prevents dealing with the inevitable leak.
The forum write-ups for these are pretty old. I'd use these instead:
Did you really pull the heater core (under the dash)? That's a pretty significant job and one I don't ever want to do again. Kudos for that if you did!