How big is this place?
Apple routers are not designed for business or industrial use. They are home devices.. most people do not live in castles or huge mansions.. if you do.. the correct way to get it installed is to ring your butler.. and say.. "James,,, see to the installation of wifi so I can get it anywhere in the house.. there's a good chap!!"
And he will order real experts in who do not use apple routers.. they use Cisco or HP or Ubiquiti etc.. which have real controls and you don't need to go around banging your head against the wall to determine its thickness or wailing in the corridors about how hard wifi is!!
If you are forced to extend wireless.. good luck.. just try and see.. there is not enough controls for you to properly manage it.
So 'Extending a network' is differnt though as for this you do actually need an Apple network as far as I can tell?
Yes, this is Apple propriety system.. other brands need not apply.
What about Dual Band Stearing?
?? Stealing, Streaming,
I do not know what Stearing means.. it sounds like cattle rustling..
The latest airport express can extend both channels apparently but Bob Timmons is the eggs spurt here on that stuff.
And if I use Airport Expresses to wirelessly extend the network does that just cause more channel issues? If I already have 1, 6 & 11 set then adding an EX wirelessly could mean that I would need to know what channel it's connected on and make sure I don't use that channel to broadcast and use the channel furtherest away?
You have no control.. your roaming system has identical SSID.. the Express will connect to whichever is the strongest signal and extend it. Remember this is domestic equipment. Not pro.
So obviously you would have more room to play with for the 5ghz, but all of your devices would need to be 5Ghz capable and close enough to want to use that over 2.4ghz, unless you could turn the 2.4ghz off, but you cannot with the Airport?
You still have no control.. if you extend a system that is setup for roaming you have no control over which unit is joined.. Extend wireless by its nature is the same wireless channel as the unit it joins with.
You do not need to use as many channels because you cannot simultaneously transmit on the main unit and the extender.. hence the dramatic drop in speed. You are picking up info a packet at a time and re-transmitting it.. avoid if possible.
WiFi is tricky man.
Only when you try to use multiple units to do the job of a pro system.. because you are using domestic equipment.