Currently the only options for date range of a Gantt chart is week, 2 weeks, month, quarter, year, 5 years. I think it would be better to have a custom option where you can put the duration you want (with an option to choose, weeks, months or years) and give it a start date. The gantt charts I've been making have been for a period of 1.5 years so 1 year doesn't fit it all and then 5 years makes everything super small. It's too large of a gap.