I have one of them, it doesnt work lol.... After my 12 channel blew for the 3rd time {and we never play it loud, I even had the electrician come out and check it to make sure it wasnt something in the house hurting the amps...} I went to the 6 zone box and the single amplifier... It has been a while now, NO problems...
I have been through this, it seems like the people happy with the 12ch amps are the people that never use them, or spend HUGE money on them... I was told by my electrician, who does all my smart home installs, he just did 46 windows for me with powered blinds that are wired to daylight sensors outside and motion sensors inside so you can set them up to be automatically closes when you are out of the room for a certain amount of time, but anyway he gave me some tips for advising customers Im building a house for that are interested in multi room audio..
1- No need for speakers in the living rooms, if they want built ins get a built in theater separate from the multi room...
2- inside and outside all at once, if they dont want outside now, sell them on running the wires so they can add it later because they will want it at some point.
3-directional speakers {the houses I build tend to be larger mid level designs, 2800-5000sq feet with 9' ceilings minimum}. My house has 9 everywhere except the formal parlor which is as high as 24', so directional speakers help point the sound where you want it..
4-sell a complete system because if not the home owner will try to finish himself and call a bunch of times asking questions I wont have the answers for...
Im a builder and I sell {or try to since it adds $'s per sq ft}, multi room audios, intercoms, smart panels, central vacuum, hardwood floors, security cameras, high eff comfort system, fresh air circulators, power awnings, ect... And when I come back to peoples homes after they have been there for a while {usually to fix the GD central vacuums}, I ask how everything is and most say "we hardley ever use the radio", I would have to say 90% lol, I honestly dont use mine, but my wife does.. When shes cleaning or gardening she uses it, and if I remember I will throw it on low when we have a party... Also when it was new, I would throw it on, and let the tv play through it if I was walking around the house.. But in my oppinion its one of them things that never pays for itself, breaks more often than any permanent household item should, and adds ZERO value to your home, it may help sell it, but most likely in 7 years when you sell {7 years is the average rite now, sick isnt it} the equipment will be grossly outdated, and new buyers will actually be trned of fby it, thinking about how much it will cost to remove!!!
Anyway, 40 speakers is A LOT, looking at your layout I thought 24 was too many...
If it was my house, I would do
4 out side {patio and porch}
2-dining
2-kitchen
2- near the entry way to have sound through that hall and stairway
2-in stairway for upstairs hall
thats 12 put them all on a imped matching box and power with one source one 2 channel amp...
Then do 2 in each bedroom with the separate sources and 10ch {12}amplifier ect... This way you will have the separate sources for the bedrooms where it will be use full, and the cost effective system down stairs for the common areas... For the 3 living rooms, simply wire it in through the home theater systems...
But 40 speakers, is just too much.. I cant picture it, you would have 2 in every room, bathroom, garage, closet... lol... I have 6 inside and 6 out and its a lot.. although I dont have them in the bedrooms, but my kids have their TV's and when they listen to music its on the ipod which is either in their ear or on a dock. And in the 2 guest bedrooms I have 2 TVs with sound bars, and my master has a surround sound... So there was never a need for it... If my wife is listening to music while shes cleaning, the upstairs hall speakers are plenty loud enough to fill the entire second floor {as long as you have the doors open}...
Anyway, hope this helps... Spend the extra money on geothermal
Also check out the emp tek ceiling speakers they are around $60 a pair, may be worth a listen...