Thanks, I will probably wait for black Friday deals to pick up Google wifi kit but mean while I will disable wifi on my N66u and connect AC88u in access mode to handle my wifi. For whatever reason it seems Tomato firmware on N66u handling packet loss much better compare to N66u and ac88u on original and merlin firmwares.
Yep Andy_82's idea was a good one. You might not even need the Google WiFi (or any other mesh system) with that in place. I only suggest the factory reset and reflash because I had an issue once when I flashed the firmware and it didn't work great. I decided to note my settings down (not use the saved settings file) and factory reset then reflash and it worked fine after that. The ac88u should be powerful enough to handle QoS on that connection.