As a general rule V1 increases with increasing TOM, see fig 4.8/4.9 in
the CAP. At some point depending on TORA, TODA and ASDA we will reach max TOM.
If the anti skid is inop the TOM and V1 is always
reduced. See page 80 in CAP.
In the GO case we have a minimum speed to accept the engine failure and
make V2 and 35ft within TODA. In the STOP case it is the maximum speed to
reject the take-off and stop within ASDA. Where these two speeds coincide gives
us V1. See graphs on page 4.3 and 4.4 of the notes.