Lateral range, you mean?

Update!

Well, I got my ES51 68x121 BB today.
Turns out it isn't symmetrical...
The drive side is 4 mm longer than the left side.
Since the entire axle is 8 mm longer than my 113 mm one, that means the right side is actually 6 mm farther out than my current one.

Now, the chainline was measured to be 42.5-43 mm. Adding 6 mm will bring that to 48.5-49 mm. Right in the middle of the 47.5-50 mm range suggested on Sheldon Brown's site.

Now, if only I'd known that pulling a crank was so damn hard when I last ordered parts... I'm sitting here without a crank puller, and no bike shops near by.
If I'm lucky, a friend om my brother's has one, but otherwise, it's a nice 7-14-day wait for me until I can get a crank puller...

Happiness is a full toolbox.

You say the BB spindle isn't symmetrical, but was the old one symmetrical? That is, maybe the difference is still split between the two sides, and none of them are symmetrical. ?

The first one was (if there's a difference, it's 1 mm or less).
The second one clearly isn't.
The drive side sticks out a lot more.