As alluded to (but not explicitly stated) in the previous log, I am layout out the board in Eagle.
In keeping with the goal of simplicity, I just used the design block for the nrf52 published by nordic semiconductors. The nRF52 has two internal regulators, an LDO regulator and an optional buck regulator. The buck regulator requires a few extra components, but it can save power in some circumstances. I wasn't hurting for space, and I expected that I would need all of the power savings I could get, so I decided to use the design with the extra components for the internal buck regulator.
for the accelerometer/magnetometers, I got the eagle library files from adafruit. Thanks adafruit. Thadafruit.
I decided to experiment with building the battery contacts into the flex PCB. we will see how well that works.