I had never known that there was a standard solfa notation, but it does not surprise me. Here & elsewhere, I have improvised & explained each time; most people seem to have no trouble with that. I find it convenient to use only one character per note.

Scale: DRMFSLTdrmfslt or drmfsltDRMFSLT, according as the song goes below or above its main octave. (It is very rare for a singable tune to do both.) Accidentals: vwxyz (defined individually as needed).

Rhythm: Let a dot stand for the continuation of a note for the time of a 16th note (or other sufficiently short duration).

Example:
m...d...S.d.....
m...d...r.r.....
m...d...f.f...f.
m..mr.r.d.......