I test rode a 56cm Serotta TI. My current bike is a 57cm Lemond. The Serotta rode great, but unsurprising felt cramped. I decided to have the seller take a short video of me riding it for secondary opinions.
While you do NOT look particularly comfortable on the bike as it is set up, however ...
IMO, if an individual knows the dimensions of ONE bike which fits well, then s/he should be able to replicate it on another frame IF the frame size of one is within a couple of centimeters of the other.
