feature tag

Appropriate feature tag for miniscule superscrpt top marks?


I need advice on the most appropriate feature tag to use for discretionary substitution of word final letters by the miniscule superscript top mark forms found in the unicode ranges [0363 - 036F] and [1DD3 - 1DE6]. I am currently using 'clig' as a working feature tag and treating each minisculle superscript as a contextual ligature of a full stop plus its base glyph to be substituted whenever a space, comma, or another full stop follows.

feature clig { # contextual liguatures
# Latin
sub period' a' @class58 by uni0363;
sub period' e' @class58 by uni0364;
sub period' i' @class58 by uni0365;
sub period' o' @class58 by uni0366;
sub period' u' @class58 by uni0367;
sub period' c' @class58 by uni0368;
} clig;