Changing column widths in main playback

No, the column widths can't be dynamically altered as you can't select them.

You can alter the format of the Main Playback display with [Format] & [Left/Right/Up/Down] arrow keys.

I thought so.  Increasing the size of the step name area is something my users often ask about.  The best I can suggest is to minimise the browser window.

Something for the wish list then:

Allow main playback columns to be resized

or

In the 'minimal' format of main playback, maximise the step name area by making the other column widths fixed.

or

Add a more minimal main playback format that gives most of the space to the step name, with minimal timing info.