Well, I guess that you can assume that the throttles are open for any measurement where maximum power output is important, so the position of the throttle is not that important.
But.. the Omega is doing something slightly different, in that it's not dealing with the tract from which a single cylinder is breathing, but a single bank. So, the situation changes from 4 or 6 intake tracts which get a pulse of air every 2 engine revolutions, to 2 tracts which each get 3 pulses every 2 revolutions of the engine. These tracts can be joined at either the plenum or in the multiram ducting, or not at all, to give 3 different lengths of intake.
The lengths can be shorter as the pulse frequency is higher, but you have the disadvantage that there will be a little scavenging and interference at the intakes inside the plenum, where 3 cylinder intakes are combined. A little compromise is required to fit it under the bonnet, as you have also observed with the clit.