That approach allows consistent settings without worrying about mic placement within the cabinet. The alternative, which I would do, to capture overdriven speaker tone before time fx, would be to mic the iso cabs, and use full-range monitor speakers at the very end of the chain. To compensate, it's practically mandatory that you use a parametric equalizer to open the sound back up again.
Someone needs to try building a very long or very large isolation cabinet or isolation closet.
If the front has a depth of 10 feet, this should be enough space to reduce the coloration sufficiently, reducing the need for post-mic equalization. Use foam strip to seal the gap. You only need to install 1 speaker, in 1 cabinet. You can leave out all the other speakers, if the power handling matches. Mount a microphone inside, facing the speaker.