Don’t go crazy if you don’t have to. We had a house in Westchester, NY that was made entirely of concrete. Floor, ceilings, etc. Circa 1911. I think concrete has improved since then. But I didn’t even bother to do a serious system in that house; I was "on the road" for some years, traveling between Scandinavia and the US, Florida and West Coast. Great years for me, professionally, but I took a dive on two channel in favor of home theatre back I the ’90s and early oughts. Now I’m back!
The big Minus K, which is what I have, will stop ’em dead. I’m not shilling. Believe me. The Minus K folks could only provide me with support up to a degree. When I wanted to do two tone arms-- implicating two thirty pound pods for support-- they weren’t interested in doing the math. I talked to a friend at CMU and a few other people, including a famous reviewer and an engineer at Penn State who was doing gob’tment work. I concluded that the Minus K was not suitable for a load that did not have a center of mass. But, I’m happy to be corrected. Right now, it’s cool, with only one arm; others may have different results, depending on situs.