An old thread but very helpful. In The Imperial March by John Williams a similar abbreviation is used however there a quarter note with three dots above is used instead of a dotted quarter for the same abbreviation of eights 3:2 tuplets. I assume it is not possible to reproduce the notation as in the photo and have correct playback?
I did try the notation using the dotted quarter note described above but actually the playback is only two dotted eights I think.