Tires / Wheels...A Plug and a question

Just yesterday I got my Velocity wheelset from Spin lite - Nice job ! Deep vees , Sapim CXRays ( 28/ 32), Ultegra hubs , and a 12/ 27 to help torque my ~ 95 Kg up the rollers around here.
I also put an S Works Mondo 21 mm on the front. A quick 10 miler left me very pleased - I was surprised at the minimal increase in harshness the skinny front gave me.
Commenting on the Stg 7 trial, I believe Bruyneel mentioned trying a smaller tire initially but ditching in in the interest of flat prevention. Are 21's the "standard" for TT's, and was he referring to going to a 19 ? Does anyone "mix" a 21 and 23 fr/ rr ? Being a lifelong motorcyclist I am used to a similar setup.
Just FYI, I had my first spoke casualty on my OEM ALX's while the above was on order ( ~ 1500 mile mark ).
My gut's churning in empathy as Floyd gets ready to ride - Let's git er done old son !