Nice tool to have for dialing in downdraught carbs, not so exact for dialing in dual sidedraughts.
The exhaust is really a series of gas pulses and the sample read by the analyser is an amalgum of all these pulses.
In a downdraught, the AF charge is premixed and distributed via the manifold. Assuming no air, vac, or HG leaks, the AF charge s/b the same in all cylinders and so the sample, and any subsequent adjustments, have real meaning and effect on all cylinders.
But, in a dual sidedraught setup, with a dedicated barrel and intake runner for each cylinder, the analyser can be fooled.
For example, you can have cylinder #1 running rich and cylinder #4 running lean, effectively cancelling each other out so far as the analyser is concerned, but could have dire consequences for the motor, especially the cylinder running lean.
While helpful, in order to truly dial-in such a setup, the analyser readings need to be confirmed by plug reading each individual cylinder, a ColorTune would work well too. But if you have to do this, perhaps the analyser is redundent.
Cheers!