OK postscript on the 700x28c tire quest.

LBS offered RiBMos, Marathon Plus, Gator/GatorHardshells, and a couple Vittoria leftovers from stock bikes. After a bit of soul searching I submitted to paying retail+ for the Ribmos. Relative to online offerings such as Scrod's, net donation to LBS for two tires was about $40. Chalk up some positive karma pour moi.

Time will tell, but from the perspective of this fixed gear neophyte's Kilo TT, the initial impression is that these are ideal urban commuter tires. Roll great, grip great, with a subtle sense of invulnerability while riding the kind of 3rd world streets one may encounter in an infrastructure-challenged American metropolis. Probably the 23c Kendas that came with the bike are a little faster on perfectly smooth asphalt, but overall I'm riding with a lot more confidence and comfort now.