I studied FS and bazi under many sifu before but remained a social practitioner only.
Always buy in a good location, as the quality of the qi is already good and u just need to tap it well. Even if u din do it that well, the amt entering the hse is enuf.

But in a bad area, and the quality bad, there is not much a super SiFu can tilt the hse to catch the god qi.

How to see a good location - go around and look at the residents. If they live well, and well off, u bet that the qi is good. If decided, the SiFu will then execute stunts to maximize the qi into your hse, depending on what u need, whether to tap the mountain for health or tap the water for wealth.

For condo, u can't hack or change the design, but if such prob exists, then use the 明堂 method to dissolve the bad chi or sha. If u go to a rich man's hse, he aways hv a space before the main door and after the main door. When bad turbulence comes to the hse, let is dissipate before the door, and if it enters the door, let it dissipate further before it enters the main living to hit the family. The last thing is to let it enter the rooms which is restful and shld be yin.

If u draw an X across hse plan, that is the heart of the hse where the main activity will take place - if the center is in the kitchen, then the family will like to eat. If it is the living room, the family will spend time there. If the X is outside the hse, then the family is seldom at home. Test this out and prove me wrong on this...

U r right that general ornamental placements like yellow rooster or blue crystal dog is marketing gimmicks - does not work.

But the metal wind chime is a technique to block the five-yellow killing star. It is a technique under the Xuan Kong flying star method. It is the few ornamental that works. It has to be metal, to create the metallic sound, does not matter how many layers. It uses the 5 element producing-destructive cycle. 5-yellow is earth, so metal weakens the effect of 5 yellow (earth element).

U r also right that there r no bad or good sectors in the hse - how can half of the imperial palace be bad for that year. It is yin-yang concept - is a son better than a daughter or day better than night. Each has a purpose. So, what if u use it wrongly? the family will bicker a bit more for the year that is all. Internal feng shui don't kill - it is the exterior mountains and the water mouths that changes ur life.

As I said, I am only a recreational enthusiast - not a pro.