Flash Cards

I'm looking to start employing flash cards as a tool for my GMing. This isn't a new trick. Most Fate system games recommend using flash cards in a number of ways. For me, my primary interest is to use them for keeping track of multiple NPCs over a long period of time in a way that has them readily available for use at game. My implementation is simple, but I figured I'd talk about it here and see what other advice you guys may have for it.

On The Card
Flash Cards, for the the few who don't understand what I mean, are simple cards of plain paper. There isn't a lot of space, far less than you'd have on a character sheet, but if you use it efficiently you can get a lot of information down. For me, this is going to be a few key pieces of information: the character's name, three to four defining characteristics, their school/class/clan, and then some key dice rolls for them (i.e.: attack roll, damage roll, etc.) The back of the card will then be used to track what happens with the characters in game. If I run out of room and the character needs more room, I'll just add another card to the character and staple them together.

With this I hope to be able to find the character quickly, have some quick reminders about what the character is like, and some quick notes on their interactions with PCs (i.e. "favorable towards Hida Bob. Dislikes Kakita Jo")

Storage
For storage wise I'm using a small box with about thirteen small compartments. This should hopefully be enough for the different categories of NPCs I am going to have (the 8 great clans, ronin, imperials, minor clans, and non-samurai.) From there the process is simple, the NPC card goes into the right section for their category, and when I need them I can find the card quickly and easily - provided that that category isn't stuffed full with tons of NPCs - with minimal disruption to the game. The box is small enough to not take up much space among the rest of my stuff at the table, and should be easily sorted.

The Hope
My hope is I can use this to populate my game with more NPCs, preferably memorable and "living" in the city. I'm also hoping I can do this and keep track of these NPCs without having to do something like bring a computer to the table, or fill up a notebook that then has to be sorted through. Flash cards are ideal for both of these due to small size, each one is a separate item, and being pre-organized. The only down side? I'll have to make all the cards for the NPCs. Then again, what GM prep doesn't involve some ink and a lot of writing?

Other Ideas
Any other tricks you guys have for using flash cards/ I'm debating also using them for locations but not sure how to organize them aside from a separate pouch for locations, which doesn't quite work as well as it sounds when you consider the variety of locations your average game based around a city will have. So, your thoughts?