ceramic bottom bracket?

I really think you should just race the multi-color single speed and forget about all that "high-tech" stuff!

My opinion which is not worth much is this: You like advancing technology as evident by your bike, wheel set, bike transport vehicle, etc.  and $100 could probably be better spent elsewhere, but you shouldn't have to replace your BB ever, so the $100 will last you a long long time. You also get the head knowledge that you have the most free spinning, latest advancement in BB technology.

Us triathletes tend to be "gear junkies" and sometimes we don't need justification and hard data, just our "gut" feelings when it comes to our sport.

Keep in mind that some people spend $800 on a fly rod and $900 on a pool cue.  Do they need it?  Does it enable them to fish and play pool 8-9 times better than a $100 item?  Probably not, but that is their passion.  How many of our friends think it's crazy what we spend on a bike!

 I can't help you on the sizing.

Ceramic bearings do make a difference.  Anything that reduces drag is good (whether it is friction or aerodynamic).  I opted for ceramic bearings when I got my Zipp Vuma cranks and am very happy with them!

Of course, making the engine more efficient and stronger is always  bets!!

everyone knows your money is better spent on ceramic headset bearings