On the 77W we use OPT in the EFB, it calculates very precise T/OFF performance figures, normally it seeks to establish Improved Climb data, but will default back to Balanced Field if necessary...the actual stopping distance is not displayed to us for an abort at V1, but observing many Max Weight take-offs at 351 Tonnes, I would estimate that the V1 point leaves as little as 3,000-3,500 feet of runway left...on a dry runway, on a wet runway with V1 reduced by 11-14 its. I can only assume it might be 4,500-5,00 feet..