I want to view the timescale in weeks and I want to shrink the horizontal scale even further. than what is currently displayed.
It seems that the scale of Gantt chart is dependant on the widest date format in its particular heading. Quite often, and in this case, the horizontal scale is fixed to the format of the secondary heading (i.e. "Mar 10").
First of all I feel it is very redundant to say the month in the primary heading and then repeat it in the secondary header. But there is no format for just the day number for the secondary.
Either there should be a manual override on the horizontal scale, or allow a "numeric day" format for the secondary header. Even better, allow user custom date formats so I could specify "dd " where the extra spaces could force the column to be slightly wider if I needed it to be.