The number of vertical grid lines would depend on the pitch bend range set at the time. Of course, each synth would have a different method of setting the current time. Also, you might complicate matters by changing pitch bend range mid project
I have actually made a Studioware panel that adds the correct pitch bend value taking into account a set pitch bend range.
Say the pitch bend range is 5 semitones but I wish to raise the pitch by 2 semitones , but starting from 3 semitones lower. The studioware panel takes care of the maths and adds the right values to generation the correct shift.