It appears like you are mounting all you can for access from a PFD/MFD hole after it would be removed - good. Look at the slide distance access for the transponder, had to lower mine 1/4", I don't remember why.
If Stein made your harness, look at the routing for all the connectors. Straight or angle, angle left or right up/down? It appears all your wiring will be under the panels - that is good, I didn't to allow room for other things, just not lower than 1 inch below the bottom rails.
Think about any component mounted forward of the sub panel. Can you connect, can you remove with one hand? Room for easy access for static, airspeed and AOA tubing? Neat and easy trumps number of connections, IMO.
Now, ensure your wires are tight (relatively) against "walls" as you may need the space later. Be compact.
Now for departure from your panel buck. Most wires can collect and go vertical along the sides of the center section. Outboard of vertical rails against the firewall, then inside the rails under the center section back to the spar. I found that wires don't criss/cross very well under the fuel valve, but do travel fine out to the outboard spar though holes. I did route my static under the upper longeron and my ELT wires but that takes preplanning and work to install some attachment points or a mounted 1/2" ID tube through the main cabin area for wire protection.
btw, I had to add an extension for my OAT probe - it's ok (per Garmin) if you use similar wire, I soldered the joints.