Since this in an open invitation for willy waving…… I’ve been round the full red loop in 1h42 (got the GPS file somewhere). For extra man-points the tyre bead gave way in my car on the way there so I had to zip tie the tyre on (too tight to buy another at the shop) for the ride, which was interesting around some of the corners with a wheel that wasn’t round, more egg shaped.
On that basis I would expect 1h30 mins or under is achievable for the better pros, although when you’re giving it some you encounter a lot of traffic so maybe the trail would need to be closed.