I’m not sure what’s available on the Skyview side, but the G5 Installation Manual I have says RS-232 inputs on the G5 should be set to MapMX (WAAS Units) or AVIATION (Non WAAS Units).
What data do you want to transfer: position, cdi ? NMEA should support position but I dont know about cdi, G5 manual doesnt say. Why do you want to transfer position ?
On skyview side you have a couple dynon formats (which G5 doesnt support) or NMEA basic or NMEA full. On G5 side you have NMEA and a couple others which dynon doesnt support. Section 8.4.13.5 in the G5 install manual describes rs232 config. For rx it doesnt say what NMEA sentences it listens for so I dont know what functionality you will get. What functionality are you looking for ?