Very similar setup
I'm going with a very similar setup, mine is an 8 so I don't have the real estate upfront. I'm remote mounting the two radios, GMA245r(intercomm), and GTX45R(adsb/inout/trans).
Most of the functionality is there, it just isn't on device buttons, it's soft keys. So there will be menus to dig through for some items that would be single buttons on the device. One potential downside is you have a few less pixels to dedicate to other info. There are discrete inputs on the systems that you can wire for specific tasks is you find them critical. IE frequency flip flop,pilot isolate, etc.
Call Garmin and ask them about what you can/can't do with the autopilot in the G3x vs the head unit. After talking to them it does everything I need. I'll be wiring my stick to a discrete input for wings level,the one physical button I want to have.
I'm not flying but I've sat in the fuselage and gone through all the normal/emergency procedures over and over to make sure that the screen has what I need. This works for me, may not work for you or your mission.
RV8 N127KT -Reserved
Tail feathers done except for tips
Wing kit 85% complete
Fuselage in progress
Dues Paid 2015