With an SCSI2SD you can most easily use an emulator.
Set up WinUAE and use the config that you actually have. All you need is the respective KickROM and the ROM for the Picasso.
As a hard drive, you can connect the SCSI2SD via USB. Just make sure to use the complete device. Don’t format under Windows!!!
With that, you quickly have a digital twin of your machine.
It may require a bit of work but will quickly pay off.
I am still not sure which packer to use for this task. The MUI38.lha needs to stay intact as otherwise it would lose a critical file. It should be possible to use zip files.
So what you could try is to create on Windows a splitted zip file with e.g. 600 kB max per file. Add them to empty ADF files with e.g. ADF Opus.
You can unzip files on the Amiga with e.g.