You can easily change the orientation of your snippets in 1SE to be vertical or horizontal.

To change the orientation of a snippet, tap Fit to Frame on the snippet screen and select Portrait for vertical or Landscape for horizontal, then tap the yellow checkmark to save. 1SE also reads a clip's own orientation, so a landscape clip opens with Landscape already selected. On the mashing screen the equivalent control is Orientation — but that one is a single toggle rather than a picker: tapping it flips the whole mash between portrait and landscape, so there is no Portrait or Landscape to choose there.