Greg Gilson
I am sure you will enjoy Sanctuary Cove, despite the architecture.
When I played the Palms, I recall the 16th having a terrible routing with a complete walk back (well, drive back) to the 17th tee. I don't recall the 6th. (I also remember missing the turn through the tunnel from the 4th to 5th, or was it the 3rd to 4th. It was easy to miss, and resulted in a very long drive up and back to find the path to the next tee).
Locally, my home club (Royal Adelaide has a partial jack-knife - it works reasonably well but does involve a walk-back. the 6th green and 8th tee are quite close, but there is a 7th hole of some 150 metres close to 6th green, followed by a 100 metre plus walk-back to the 8th tee. In Mackenzie's plan, 8 was to become a long 4 with the tee placed probably close to today's 12th tee - a better routing (12 would have stayed as a less-long par 3, perhaps from the ladies tee today).
As I said, it works reasonably well, despite the walk back.
The other Jacknife that often occurs is the temporary or 19th hole. Kooyonga's 11A is an example, with a good hole running parallel to the 11th hole with adjacent tees. Play the 170 metre par 3, then walk back the 170 metres to the 11th tee. My club (Royal Adelaide) is building a 17A hole which is a short 3 of 125 metres (I think), with a tee near the 18th tee, playing away from the 18th and then involving a walkback of 125 metres.
I can accept jack-knifes on temporary holes, and can also accept a 120 metre jack-knife somewhere on a course, if the rest of the course is well routed and has short transitions (walkable) from green to tee. I am less generous to jack-knifes that really require cart golf transfers.
James B