After a *long* fight with it, it is now available in .dsk format.

The 18-sector tracks on master side A were probably used just for faster loading.  There was plenty of room to convert them to 16-sector tracks. 
Master side B was the tricky one later. 
The first two tracks were the fonts, for which there was also plenty of room to convert to 16-sector tracks.  This was followed by some 18-sector tracks which are completely unreferenced, and that was very lucky for us, because in the absence of a compression method, some of them had to be used for the 16-sector conversion. 
Tracks $16+ are 18-sector tracks.  Converting them to 16-sector tracks required two additional tracks, which we acquire from the unused ones.  However, it is not as simple as just converting them.  The models and decals are stored in the tracks $16+, and to avoid the need to understand how exactly they are loaded (the loads are overlapping, so finding the right offsets might be tricky), it was necessary to alter the tables in the GENTOY and GEDIT files.  By moving the DOS files down by two tracks, we can leave the models and decals as one big blob of data, just like it was before.  The only difference being the starting track is now two tracks earlier, too. 
Finally, the data disks.  They were entirely 18-sector tracks, and completely full.  They needed to be compressed.
Fortunately, they are read in chunks of 9 sectors at a time, so it was simply a matter of compressing the content enough to convert 9x2 sectors to 8x2 sectors.