Nigel, thanks... I'll reword that then.
In the 70's I became aware (and understood the reason was some slow acceleration aciidents) that either a suggestion had been made or it had actually been introduced by some airlines - the practice of 'timing' the roll up to V1.
I imagine if it was tested, trialled or used in anger, that a pre-V1 decision point of speed Vs time would have been implemented. That is, V1 itself would not have been the timed point...
Remember also that at that time, a 3rd crew member, namely flight engineer was common, who perhaps would have been the nominee for such a task...
Remember also that at that time, airliners had low-bypass engines and did not have the phenomenal acceleration they do today - everything was a good degree more marginal I imagine.