To answer your question – which was the original intent of this help request, the aim is fundamentally data logging. Users will log data (at 20Hz, say; multiple parameters) then occasionally pull them off for external analysis, delete, and start again. So I don’t think wear levelling is actually an issue; just speed and ease of pulling data off to spit out over USB or Bluetooth LE, on an occasional basis.
Hmmm.. If you don't care about about wear-leveling but you want to get data from USB (via USB MSC?), then you should consider FAT. You can export and mount the SPI FLASH-based FAT file system on any host just as though it were a any other USB FLASH driver.
FLASH file systems only exist to handle wear-leveling and bad block handling. (I think I do have some ancient FAT bad block logic somewhere that I never got merged upstream).
