I use Typing Tutor 7 to train
http://thepiratebay.org/torrent/3348426/Typing_Tutor_7

It trains you to type the number row like this.

`1 left pinkie, 2 left ring, 3 left middle, 45 left index.
67 right index, 8 right middle, 9 right ring, 0-= right pinkie.

It also trains you to type number with the numpad too.

~ 1 2 3 4 5       6 7 8  9   0 - = BS
R R R M M M      I  M M M  R R R R

sometime when I type 12 I use adaptive technique so when I hit one with my ring I hit 2 with my middle.  My way does not require much hand movement and If you get used to it, it is easy.

I could not touch type the number row before I got my non-staggered Kinesis. The locations feel like they're shifted one to the right compared to normal keyboards and it's especially confusing to have 6 on the right hand when my NEK4000 had taught me to use the left hand for it. But enough complaining, because now I can actually touch type them!

1 2 3 4 5    6 7 8 9 0
p r m i  i    i  i m r p

A major reason for not going with the classic setup (that Typing Tutor uses) is if you want to keep your wrists straight while typing like I do. Then the index finger stretches to the '6' key will be too long for the right index finger which would lead to muscle strain. Also, the middle fingers are strong and in need of gainful employment whereas the index fingers are in general almost overused - they have to handle a lot of keys each.

Typing '6' with the right hand is a debated issue. Some split keyboards have that number on the left side anyway! Because that makes the most sense geometrically.

So I'd recommend the `1|2|34|56||=7|89|0- approach (well, I've moved the '=' into the middle as part of the Wide Ergo mod but nevermind that) that Legolan advocates, with just a bit of flexibility thrown in for some number digraphs.