More precise \rlaps for the previous MWE:

\hbox{\rlap{\ruledhbox {\transparentgreen\tfx  c\symbol{glottalhamzah}c}}%
     \hskip-.075em \ruledhbox {\transparentred      c\symbol{glottalhamzah}c}}

\hbox{\rlap{\ruledhbox {\transparentgreen\tfx  c\symbol{glottalayn}c}}%
     \hskip-.075em \ruledhbox {\transparentred      c\symbol{glottalayn}c}}

--
Professor Idris Samawi Hamid
Department of Philosophy
Colorado State University
Fort Collins, CO 80523
On Aug 12, 2023, 4:11 PM -0600, Idris Samawi Hamid ادريس سماوي حامد <ishamid@colostate.edu>, wrote:


     \hbox{\rlap{\ruledhbox {\transparentgreen\tfx  c\symbol{glottalhamzah}c}}%
            \hskip-.09em     \ruledhbox {\transparentred        c\symbol{glottalhamzah}c}}

     \hbox{\rlap{\ruledhbox {\transparentgreen\tfx  c\symbol{glottalayn}c}}%
                 \ruledhbox {\transparentred        c\symbol{glottalayn}c}}

:
Note the \rlap's (see attached pdf): we see that \tfx doesn't scale the \symbol, although \tfa and higher do work.