Hey trirusty, im not James but I know the answer!
Sometimes when old threads get resurrected they can get over-looked...
He used wide and thick Continental gator skin clinchers
If every second counts.
On a bike course that has LONG, FAST and SHARP descents with ruff french roads.
That in the end a pragmatic equipment choice is faster and safer than a theoretic equipment choice!
I would wager that if he used (James please correct me if you dis-agree) skinny tubulars.
He and like most triathletes would have compromised both their confidence and performance!