XPlot plotly barplots superposition

Is is possible to have bar charts with different bar widths superposed in one chart?
I want to display weekly and monthly values on a bar chart. So for each month I would have 1 wide bar + 1 narrower bar per week starting in that month. I have the values and individual bar charts setup, and I can display each in its own chart, but combining them with

[weeklyBars; monthlyBars]|> Chart.Plot

results in small bar widths for both. Anyone having done this?