When I state that the aircraft is irrelevant, I am referring to regulations, not what the FMC spits out.
The FMC takes into account the runway length, like your QRH speeds. The important issue here is the ASDA. Speeds are solely based on stopping distance an screen height at the end of your runway.
The WAT charts, or runway analasis takes into account your second segment climb requirements, further augmented by wind and slope.
A max allowed trust reduction of 25% might again change the picture as now your screen height could result in being much more than 35 feet, in case of a long runway. However the V1 for being able to stop remains the same.
Then the operator has some leeway in choosing the speed ratios, as long as he stays within regulations.
Al those parameters are fed into a computer now, and no wonder you end up with different speeds for different trust settings.
Vr is not by definition based on optimum V1.
A simple question, not a simple answer.