I?ve got almost the same equipment in my RV-9A. My preferred screen configuration (so far) is engine gauges outboard on both sides, half screen PFDs on both sides, half screen MFDs in the center part of each G3X. Send me an email address and I?ll send you a picture. Hardware arrangement is G3X ? 3? instruments ? radio stack ? G3X
? You will manipulate the GTN-650 a whole lot, the G3X PFD not nearly so much. GTN should go in the center, absolutely. No problems reading the right side G3X
? Extra credit for grouping the switches, instead of having a long row of identical switches.
? Pitot heat gets used rarely ? put the fuel pump there, where it?s conspicuous
? Audio panel probably won?t get used all that much since each comm radio is a flip-flop plus monitor. And those have traditionally gone on the top due to space reasons, not necessarily because it made sense.
? Get the autopilot controller with dedicated heading and altitude knobs, as others have suggested
? Because of the envelope protection, I have the autopilot on all the time. That would suggest moving it with the other switches that are on all the time
? You?ll use strobes more than NAV lights. Put strobe switch on the end where it?s more visible. Or, since strobes go off when pitot heat goes on (in a cloud), and vice versa, you could pair up the strobes and pitot heat.
? Why are the dimmers off in Siberia? You?ve got room for them on the left
? Add power plugs on both sides, and USB ports as well. Can?t have too many
? Don?t know what AVI is. If it is avionics master (I purposely did not install same in my -9A), put it away from switches that get turned on and off. Put it with the other always on switches. But, given how much setup there is for the avionics, being able to power them up without the rest of the electronics being on (this is not the traditional way an avionics master is wired) is worth considering. Better yet is to have a way to power the avionics / recharge the battery without taking the cowl off.
? While it is traditional to have the electrical switches in front of the pilot, that?s not a requirement. On my Cessna 175, they were across the top of the panel from the center stack and to the right. Easy to get used to , easy to find, did not take up prime panel real estate. Definitely worth considering if you want more space above / below the G3X. Check it out on somebody else?s RV-10 and see if it makes sense for your airplane. (You don?t have a control wheel hiding the bottom of the panel).
? Consider a panel mount transponder. Easy to change codes when you?re busy, gives you an extra timer with dedicated buttons.
? With a center stack, you could put in an Aera GPS or something like that on top. Gives you an extra screen as well as backup nav independent of the electrical system (yes, I say that you have extra electrical sources)
? The -9A came with clips across the top of the panel to hold wiring for handheld devices. Very handy.
? I have a GDL-39 portable atop the panel, with a cable dedicated to connect it to the left side G3X. Found out that the right side G3X could see traffic but not weather. Solution was to connect the right side G3X to the GDL39 via Bluetooth (no extra hardware required).
? I have a Dynon D2 specifically because it has no pitot / static. In a pinch, I?ll take GPS altitude and won?t care if I?m a bit off (in altitude, that is) and the RVs are easy to land without an airspeed.
The G3X / GTN have truly awesome capability, but have a lot of learning curve, too, and some of that will be experience and oral tradition ? the manuals are industry standard quality, which is to say, mediocre. Don?t count on hopping in it and flying IFR without adequate practice.
I don?t know about the RV-10 panel structural limitations, so I may have missed something there. This reply is a bit long, but hope it?s helpful.