I've done some load testing of my first prototype power "mezzanine" board (can't say "hat")    The voltage drop of powering the RPi touchscreen off of the GPIO while the tinker is on micro-USB is insane, I was reading 3.9 Volts on the USB ports when I ran minerd --benchmark.  I may have finally worn out the Micro-USB connector...   This is a project for learning the ins and outs of kicad and get an idea of the capabilities of the PCB houses I have reasonably fast access to (Chinese one