First, I would like to say sorry for not posting any progress here.

I was moving my home laboratory to new location. More space, more gadgets, new ideas ;).

Previous concept has some issues. Like zero-cross detection was not working like expectations. (I have already published working idea).
Another problem was with temperature measuring. Maybe you know that, temperature is changing in uV. Previous solution has lot of noise on AMP inputs. So I have modified the measuring technique a little bit. Now I am measuring it like a differential. So noise is on the both of inputs and it equals to quite good signal.

Last problem was with the switching itself. I was noticed on this problem by @Attila Kovács . He gave me a lot of advice, which I would like to say, thank you.

After some modifications I have finished a new PCB design v1.1. (I hope, this is the last one :) ).

Now I have to wait for fabrication... .