I'm working on an OT font that had both short and long descenders. Ideally I would make this kind of thing a stylistic set, but no apps currently support stylistic sets (to my knowledge, i could be wrong). In the meantime i'm thinking the most appropriate feature to use for this would be the "calt" feature and having an indentical "ss" feature for when apps are made that support stylistic sets. is this the best solution? does anyone forsee any problems with this/have any suggestions?