Here is a proposed structure for supplemental data
<scriptData type="Latn" lines="top-to-bottom" characters="left-to-right" spaces="true" shaping="minimal" usage="recommended" originRegion="150" sample="A">
shaping = (in normal usage)
usage = value in UAX31
originRegion = continent or subcontinent where script originated. Following the Unicode book / charts (see the spreadsheet).
sample = character with distinctive glyph that can be used to represent the script in icons (eg missing glyph)
The orientation field in a locale would only be used for overriding.