Well, as I say, it's a nit-pick. Minor stuff, and unnoticeable to most. The cylinders on each cylinder bank of the Ardun are arranged in pairs, the cylinders in each pair being a mirror image of each other in terms of valve train/rocker arm configuration. A v-8 engine will have two of these 'pairs' on each side of course, and a v'12 would have three of these 'pairs'. For a v-12 such a configuration would have spark plugs arranged thus; oo oo oo. With significant and unnecessary re-working of the valve train you could possibly have a plug arrangement of oo o o oo, but in the real world no one would do this.
The spark plug configuration on the 3D printed v-12 Ardun is ooo ooo. If numbering the cylinders on one side 1-6 from front to back, cylinder 1 would have one plug, cylinder 2 would have two plugs, cylinders 3 & 4 would have no plugs, 5 would have two and 6 would have one.
It's all a bit pedantic, really, but I noticed when viewing the photos. The vast majority will likely not know the difference. By no means do I wish to detract from your stellar build. Cheers.