The best workaround is to get a bomebox or an equivalent MIDI translator box, and to convert some other MIDI data into pgm changes. Otherwise, you need to use the 4 parts per bank, and use diff banks if you need more than 4. Or then you need to use the OT’s internal “pgm chng on pattern change” feature, which originally caused your headaches, but then you will be forced to use patch 1 for pattn 1 etc (ie. alot of copying of patches on your evolver)

Also, regarding the evolver changing its pgm at the end of a pattern, this is a default behaviour on the evolver for patches that have a sequence. You can disable this behaviour from evolver’s settings IIRC