which carb is the "reference" carb for syncing?

[D98vs1400]

Not to reignite this already mutilated horse of a topic, but i watched this video that brought up a topic/concept i hadnt heard of before. this guy was syncing carbs and he was talking about "early" model and "late" model carbs had 1 major difference: a reference carb.

[YoutubeURL][/YoutubeURL]

apparently there is 1 carb in the series that is not adjustable and so the vacuum settings are measured on that one, and the remaining carbs are adjusted based on that reference one. Granted he was working with a 4 cylinder, not a v-twin, but i was wondering if our bikes had the same thing going where one of the 2, was a reference and the other was adjusted to that?

[hillsy v2]

With an in line 4 you either have one reference carb or 2 sets of 2 carbs.

This doesn't apply to carbs that are not in banks / rows.

[Lechy]

On the Intruders, idle and running synch are both adjusted on the front carb(#2 cylinder), so by definition the rear carb would be the reference carb.
Info here: viewtopic.php?f=32&t=4139

[Herb]

On the Intruders, idle and running synch are both adjusted on the front carb(#2 cylinder), so by definition the rear carb would be the reference carb.
Info here: viewtopic.php?f=32&t=4139

But you have to set the rear carb first and it does require setting.