downgraded to the 2.0+, works fine again.

I'm not sure this is a bug. The option in the advanced section only modifies the size of the sub-questions (column 1). It doesn't modify the size of the answers columns (column 2-9 in the supplied test survey). So I don't believe you can modify the size of the answer columns through the lime survey interface; it looks to be auto-generated based on the question size and available space.

I checked version 2.0+ and 2.5b and the display of the test survey is identical. It seems unevenly spaced in both.

The reason for the uneven spacing is the column headers. Specifically 'tesetstetast' and 'asdasdafsfasfasf'. They are continuos words and the renderer doesn't know how to handle them in the spacing constraints. So it breaks the spacing constraints rather than breaking the words in two. If you insert breaks into those answers (something like 'tes etst etast' or 'asdas dafsfa sfasf') then the question display renders with even spacing.

ssinnott, thanks for your feedback.
Seems like this should be fixed in the template css to me, closing the ticket.