If it would help, here's is the user manual and the patch map for the 81Z:

User manual here:
http://thesnowfields.com/manuals/Yamaha%20TX81Z.pdf

Original patch maps:
http://www.synthzone.com/midi/yamaha/tx81z/TX81Z.ins


And some additional patches here:
http://patcharena.com/synths/yamaha-tx81z/

Micro tuning resource (half way down)
https://mgregory22.me/tx81z/index.html

Another thought might be to consider Kontakt's FM8 VSTi. At $149 and over 900 patches, it might be an alternative and may get around some of the limitations mentioned here by other suers.

Jeff


Win11, Intel i7 7700K 4.2Ghz, 32Gb RAM, 2x1Tb HD, 500Gb NVMe, BIAB/RB 2025, MOTU 828MK3 audio, MOTU Midi Express, Yamaha Montage 7, DX7II, TX802, Motif XS Rack, Roland Fantom XR Rack, Oberheim Matrix 1000, VoiceLive3 Extreme, Kontakt 6, SampleTank 4.3