@eloBROWN 

I use my iPad to check my wifi speeds. In my case I have a router with different ssids which makes it easy.

For mesh system, you need to get to an area where you know which node you are on.

you need to place the mesh nodes in a strong wifi area of the router and extent the signal from there. Most common mistake is to put the node to far from the main node/router. 
 

if they can be connected via ethernet that is much better to have a wired backhaul then you do not have to worry about distance. 
 

My research shows a designed mesh system such as deco is better than routers in mesh mode and is easier to set up and maintain. Also easier to add more nodes later if needed.