Hiding columns can get a little tricky due to how data is stored within a table regarding columns...
The reason why your column automatically resize to 0.7" is because of the order of columns and the order of widths per column.
If you have a look at your table property columnWidths within the XML, you can see how the columns are split with space between each other. Now because you have hidden column 1 and column 2, the first column visible remains 0.7".. so you would have to handle this part as well.
When removing the columns you can simply change the behaviour using the following statement: