Getting back on track. Met my weekly commitment again. 3.1 hours per day for 4 days.
Continued work on RS-232 and ARINC connections document, studied manuals more and sent the remaining open questions in a different format to Garmin. I'm still confused, but understand my questions better.
Added all the Garmin serial numbers to my Garmin parts spreadsheet and entered them into a Garmin website to confirm they were correct. Need to call Garmin before submitting all of them.
Worked with Gigaflight CAN bus cable to verify the acceptable solder sleeve size and started practice with stripping the cable for solder sleeves and splices.