I've also been pushing the limits of my Solo's - seeing how far they can fly with a stable video feed. I have two Solo's and I've done identical mods on each one that include:
MikroTik 800mw Wifi cards
Alfa antennas
Beitian BN-800 GPS (M8N) - with my custom designed mounting fixture
Cirocomm GPS antennas replaced with a Taoglas antenna specifically designed for optimum reception of Glonass satellites
3DR EMI absorber GPS shield
It was a smooth flight (aside from the wind) with 20 to 21 sats locked the entire time, and my friends were impressed with the Solo. My target was a water tower that was 8420 feet away.
Youtube video here (read the timeline commentary in the description - and select 1080P to see all the details)
Congratulations on the safe well executed flight. Glad to see you brought along two spotters to stay within the guidelines....