I did not code FF14 and have little understanding about how it is coded or why there always seems to be reason for why something cannot be done but 88 bits is not a lot of data.
There are 8,000,000 bits in a single megabyte. Perhaps you meant bytes? Even still there are 1000000 bytes in a single megabyte. Beside this glamour should not be coupled to the actual item in the way it appears to be. Soooo create table for character inside of database > create array for glamour options > create array for potential glamour options player has access too > create single array within character database table for glamour sets.
The only additional data that would be required is one single table of which glamour options a player has access too and what they have glamoured too. What do I know though, I have not coded in fricken ages. I only know the way we handled this when developing emulators for various things. Character data was stored using sql tables and took up very little space. One thousand players worth of sql entries equaled umm, roughly fifty megabytes of space. It could increase to two hundred megabytes when backing up tables for character recovery but still not that bad. The average enterprise grade drive is five terabytes. Enterprise grade SSDs can be found in the multiple terabyte size too.
"we're definitely out of space to save such data" That is kinda concerning for reasons varied and I wonder how their system works. My assumption is that rather than uncouple item data from item display data they simply copy everything hence glamour dresser. The item in there is the full item.. which is silly. Same should be case with inventory, all that is required is a reference to the item the character table does not require one entire copy of the item data for that item. This was not how server emulators did it even back in 2005. Perplexing.