Not sure if it is available.
Already in 2004, it was mentioned in bug 55830:
We have no plans to expose the "horizontal/vertical" fastview option as API (since this concept might be removed in the future in favor of 2 resize sashes).
And the 2005 question about the same feature went unanswered!
I currently add a fast view to my perspective...
layout.addFastView(IConsoleConstants.ID_CONSOLE_VIEW, 0.35f);
How can I programmatically set this view to default to a horizontal orientation?
I assume this is not possible to do through the API?
THe current IPageLayout
doesn't seem to have any parameter for the orientation.