Some quick signal strengths using WiFi Man on Android.
The rental house I’m in is a bit weird and sometimes I think the guy who renovated the house might have used lead to line the walls. Note the Convexa is a 2 node mesh at the moment so you have to ensure you’re looking at the B2 2.4Ghz for a proper comparison as I move around the house.
Flint appears to perform the best both over the 2.4 and 5Ghz
Slate AX seems to do well close/medium over Velica but then seems to lose a bit.
Next to the routers
In the middle of the house
Furthest point from the routers