Deflt track size and resizing mutliple

Hi. To set as default height, right click in the track pane, and select set as default height towards the bottom of the menu.
To resize multiple tracks: Select tracks, and Shift +drag.
Hope it helps.
All the best.

When you lock the height of a track, its height does not change when you use a Zoom or Fit command. When a track’s height is locked, you can still drag the track strip’s lower border to adjust the track’s height. After you drag the border, the altered track height becomes the track’s locked height.