I'd go with whatever tire type the rear is. Just makes race logistics slightly easier to not have to be prepared to repair both a tubular and a clincher.

Probably marginal actual speed differences.

TT is flat and done. Not triathlon. Whatever is ready for rave day is pretty much it.

Go with deeper if you can handle it. IF the tub is latex also it should be close to the clincher. Lots of tubs are butyl though.

I'm a TTer. I've gotten flats warming up, recon rides, etc.. You still need to deal with flats. It's a bit easier when it's all one system.

I didnt think of that.

But I bring all my wheels with me. My HED 6+ front, Flo 90 rear, HED disc, and HED 9+ front. One each. So I could flat two in warmup and still roll the race. No matter the type tire.

Yeah, for super A races, I bring a full backup wheelset, which is the way to go. You don't want the stress of tires changes when you're watching the start clock.

Consider that the body weight is on the rear wheel, whatever the seat position is, thus cross winds move the front wheel away from planned path. The taller the rim and the larger the overall seal effect (e.g. with large carbon spokes instead of traditional thin metal threads), the larger the instability and slicing through the wind becomes difficult or unthinkable. If the race is short (e.g. 10 miles), even with strong cross winds, you may accept the instability. On a century ride cross winds become a problem, sometime unexpected. 404 has shallower rim relatively to 808.
With any wind, the rear disc is manageable because the bike is pushed to the ground by the body weight. I regretted doing a full distance Ironman with a front HED 3D+, because of strong cross winds, but I never regretted 808 rear, as I never felt the wind blowing myself away, as for example when passed by a large truck on any condition. I saw that riders with disc on the strong cross winds day didn't have problems of rear instability, while everybody with deep front wheels had sudden instability, adding fatigue and with higher than usual DNF.
Obviously adding mock weight to the front part of the bike to keep the front wheel down is not part of the optimal solution.

For TT, prioritise aero on the front and rolling resistance in the rear.

Glue a Corsa Speed (23) on the 808FC, that will be the fastest option as long as you glue it on nicely!

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AeroCoach UK
http://www.aero-coach.co.uk

Thanks for the tip. I kinda expected that would be the fastest option, but was hoping someone would chime in saying the SC tubular was testing just as fast (can’t seem to find any data on it)

Yes that's right, we haven't published our tubular data yet but a tubular Corsa Speed is basically the same speed as the clincher/tubeless one as long as you've glued it on straight etc.

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AeroCoach UK
http://www.aero-coach.co.uk