Streamlining was my goal as well.
More specifically, I wanted to be able to type an entire address without moving any finger more than one key from its home position, and I accomplished that with the layout I posted there.

I went just a bit bigger than you, on the case, because my secondary goal was to avoid muscle memory conflicts, given that I have to use other people's keyboards/computers quite frequently.
My layout feels "mostly normal", when compared to the 60% portion of a standard keyboard, so I don't have to fight muscle memory on other people's equipment.