@genphreak,
Sorry to be so slow getting back to you on this one, Xmas silly season and all, I have been a bit slack at keeping up on my correspondence.
In answer to your question, my seats are unbelievably soft and supply, what I did to ensure 100% penetration of the Rejuvenator, was to first wet sand (using Prepping agent) the seats with 600 grade wet and dry, to remove any previous protective coatings such as Armoural or similar, then apply a liberal coating of the rejuvenator and wrapped the seats in Black Garbage bags and let them sweat in warmth of the garage (Not direct sunlight) for 3 days.
Next step I used the Cleaning Solution and wiped them down with a damp cloth of prepping agent again. I didn't have enough to do another heavy coat of Rejuvenator, but did do a lighter coat and wrapped them up again for another couple of days. My reasoning for doing it a second time was to use the first application of rejuvenator to completely expel all traces of dirt and grime and the sec on application was to get maximum moisture back into the leather.
Your seats may not be in as bad a condition (or neglected) as much as mine were, as the PO's of this vehicle has seen it's full life in the harsh Qld sunshine and I doubt the leather was treated at all in that time. Hence my complete surprise at how well the Leatherique products worked, they completely exceeded my expectations.