Opinion:

Done it twice and that course is *mostly * predominant strong head and tail wind.

One decent section on the back side where you get a bit of cross wind, I was a little unsettled with h3 front and stinger disk.

Regarding tire, I run tubulars and have gone to a shwalbe 21 on the front h3. It doesn't sit round like the corsas but I am giving something up on butyl tube.... I am struggling to find something perfect for that front wheel. Even had an old conti tempo with latex at 19mm but flatted at a 40km tt when I looked at it funny.

If clinchers you will have a lot better choices for tires.

2c

Just clinchers here but all we have for tyres for now are 23s.

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http://www.fitspeek.com the Fraser Valley's fitness, wellness, and endurance sports podcast

If can do OK with handling then double h3.

If not then h3 404 front probably isn't much worse.

Regardless if this is a targeted race he should find 100$ or so for race day and depending on condition upgrade his tires.

Bonus is lots of great info on here for what would be best clincher option for him.

Cheers,
Maurice