MAS,
So these guys are all giving you very good and technical information on technical wheeling in any rig and particularly a Subaru. As I understand it, you're not that interested in technical wheeling in your OB, but rather getting off the beaten track and certainly not close to or beyond the point of no return.
One thing I've learned, particularly with grades....if you go down, remember you may need to come back up. Personally this used to be a greater concern before my low range modification, but still true now. I've learned quite a bit about my low's capabilities since installing it and going out on a big-boy run (lockhart basin) in a Subaru.
I am looking at the calendar and weather to see when I might be able to pull off a WR in a day run and get you some first hand info. I almost almost considered it today, but a friend reported back the shafer trail is still snow and ice packed, so i bailed on the thought.
Ultimately I feel pretty well your OB could pull off the WR. Its really not that technical overall, just a couple of spots, and even there its just grade which your H-6 5EAT won't have a problem with. Approach and departure angles probably won't be a serious variable, but may factor in line choice here and there.
Again, do you have a permit for the trip (i.e. how many days do you plan to take?) or are you going for the LOOOOOONG day trip? I still advise having company and not a solo run (never mind that i was considering a solo run today, but I know the area, friends would have been in the loop, I would have check-in points, etc. etc.
And please do, keep in touch with me as the trip comes near.
Side note:
check this info out for the shafer-potash run, as I said similar to the long canyon run.
https://www.utahgeology.org/road_logs/uga-29_first_edition/NP_guide/shafertr.pdf
https://www.traildamage.com/trails/index.php?id=280
Ciao,
-mark-