The TT race bike. I wrote down my existing fit coordinates, then looked up the bike's geometry chart online and made sure I had some play each way to adjust things.
It was a Pros Closet used bike, only short term complaint was either they or the prior user assembled the stack spacers wrong. There's a hidden ferrule that keeps the bolts digging further into the base bar than designed. They were missing. Caught in time when I went to make a fit update later.
Buying sight unseen is fine if you bother to measure your existing bike fits and lookup or ask for geometry of what you are buying. You can't realistically feel out "road feel" on a spin around the block.