@razerdog,
[UPDATE]
We have released chart v3.15.12 with the above fix. Please refer to the release blog for more information. Do download the latest version from our download page and let us know your feedback.
Stacked Column charts are plotted when multiseries with aligned x-values are plotted on same scale. We suggest you to use column chart in this case. Please take a look at this updated JSFiddle.
However, if you like to set the column width manually in any of the column or bar charts, you can use dataPointWidth property to do so.
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Indranil Deo
Team CanvasJS