Old Yale Cabinet Lock

[Silverado]

I've come across a challenge and I would like to ask for some assistance!
I know you like lever locks ratlock! Maybe you can help? Any advice from anyone is appreciated.

I was asked to open up a locker bank which has one large locker and 6 small lockers in it. The big locker was already unlocked which helped out a lot because I took the locking mechanism off for research purposes. Turns out it's a Yale lever lock stamped with the following:
YALE, Made in USA, 9ME 3337, and 9ME 3343.

I am guessing the whole assembly is older than me, and it's clear that these take flat steel keys. Looks like 3 or 4 levers but I'm not certain as I've not disassembled the one I removed yet.

My question though, what makes the best tools for these? My goal is to get the lockers opened remove each lock and make new keys for them. I found a document of ILCO flat steel blanks but there are so many for Yale I don't know which one would go to this lock.

I intend to disassemble and photograph this after work today so pictures coming a bit later.

[billdeserthills]

The easiest way would be to just make the key for each, that way you will accomplish both tasks at the same time.
Start by obtaining the correct flat steel blank, and I bet you know the rest....

[Silverado]

Turns out they're 7 levers. I figured making keys for them would be the easiest route. All the levers are so tiny it makes me think making a tool for this would be much more difficult. I'll still put some pictures up later because the inner workings on these are so neat...it's like looking at the guts of a fancy watch.

[Silverado]

So I am having some trouble with this. I can't seem to find a key blank that matches...
The length from the bottom of the lock to the keyway is about 1.25", and the keyway measures .06" thick and .312" wide....

What measurements would be the best blank? I'm looking at the ilco 1370 which is showing up at .050" thickness and .305" width. The only picture I have appears as though the blank is much longer than it needs to be.
Or should I go with something that's got different measurements? I'm just not sure how much wiggle room it ought to have.