Well it will still be on my road bike, so I wouldn't necessarily be starting over from scratch (as related to riding a TT bike for the first time). I would just have to put some hours in on the aerobars, which I have always done in the past. Was mainly just looking for some general guidelines, but I think a 20-min test would be a start. I might actually push that down to a 15-min test and set a baseline from there seeing as all of my times from last year were below 15' (and distances likely aren't changing this year from what I have seen on current flyers).