Problem when simulate K factor

Hi everyone,
I am designing a logarithmic amplifier. The selected topology as in the photo attached below.
The circuit include some amplifier cells, rectifiers and input/output buffer
Input buffer and Amplifier cells are RF circuit obviously.
Rectifiers are half RF (input) and half DC (output)
Output is DC circuit.
The question is when I simulate S-parameter for K-factor value, should I put the output terminal at the last amplifier cell output (point A) or at the final output (point B) or what? and what should be the terminal resistance if the answer is "at last amp cell output"? 50 Ohm or a very large value?

Thanks for help in advance.

Anyone helps me plz!