To adjust column widths hover between the columns to make the layout helper appear, then when you hover over the layout helper it changes to a + and a two-way arrow. You can then click on the two way arrow and drag it left or right to resize the columns.
How to delete a column
To delete a column hover above the column and the layout helper will change to a bin, which you can click to remove the column.
SquaredUp will resize a diagram in the Visio tile to fill the column width. Resizing the column will make the diagram increase or decrease in size accordingly. You can also affect the size a Visio diagram is displayed in SquaredUp by adding or removing the white space around the diagram in Visio as described below and in this article https://support.microsoft.com/en-us/kb/285024.
If you would like your Visio diagram to appear smaller within the column: In Visio increase the size of the white space (padding) or page around the diagram by holding down CTRL and dragging the corner of the page. Then save the SVG, and drag the new SVG file into the SquaredUp Visio section again.
If you would like your Visio diagram to appear larger within the column: In Visio reduce the size of the white space around the diagram, save the SVG and drag the new SVG file into the Visio section again.