Avionics I/O and Power Distribution

First long post! I have been collecting the required tools to start so I have been starting some non-structural elements of the build. Things like Avionics I/O and Electrical Power Distribution don't require any tools to design so I figured why not work on that while I wait.

Power Distribution: I'm using draw.io for the rough draft of the power schematic. I will likely switch to a wire schematic and a quick I/O table next. There's a lot going on in this so here are the basics. The bus voltage is 28VDC. I am wanting to use the PPS and VP-X systems from Vertical power and the System 32 Electronic Ignition and Fuel Injection from EFII. There are plenty of benefits to using a modern ECU controlled fuel injection and ignition system, however one draw back is the increased importance of having a very robust electronic power generation and distribution system (No electrons flowing = the propeller stops spinning). By looking at the guidance material from Vertical Power and EFII, I have come up with a distribution architecture that I feel comfortable will be as reliable as practical to keep the engine running when a component fails. Basically I have the primary distribution bus feeding a main bus and an essential bus through the PPS and VP-X system. The PPS and VP-X system also distributes power to the DC-DC converter1 that provides power to ECU1 and electronic components of the System 32 EFII. The backup power bus is also 28VDC and can be powered by the primary system. The backup system powers backup IFR systems through a fuse box as well as DC-DC converter2 that provides power to ECU2 and the electronic components of the System 32 EFII. The purpose of the two power systems is such that on the primary bus, if the PPS, VPX, DC-DC converter1, or ECU1 fails, the backup system can keep the engine running and the navigation systems functioning in an IFR situation.

Avionics I/O: I'm pretty familiar with Garmin Avionics, just not familiar with G3X components so there was a learning curve reading the G3X install manual but it was a small one. Basically I'm planning to use the core G3X system (GDU 460, GSU 73, etx.) with a GTN750 and GTN650 navigators, a GMA35c, GTX 45R, GDL 51R, GHA 15, and a G5 Standby. With all of that there are a few recommended wiring schematics in the install manuals and using those and the recommended communication busses- I captured all the I/O in an excel sheet that I took a screenshot of in the attached image.