Two 92mm fans does have a bit more surface area than a single 120mm fan (about 15% more I believe), but, I think with the way the fan is going to be sandwhiched between the core and the booster cell plate, static pressure is likely going to be more important than air surface area movement. Especially considering from what it seems, the 92mm would be stacked one over the other. If I'm correct about how the booster cell panel works, the vast majority of it will likely be blocked but perhaps some air will squeeze down by the PSU cables and maybe into the GPU compartment.
I think if you had two 92mm fans in place, one of the fans would be practically useless. I think given that the 120mm will likely have better overlap to where it can actually send air in usable manner, as well as the static pressure benefit of most 120mm fans over 92mm fans, it's probably best to have just a 120mm only design, instead of a 120mm or 92x184 set up.
I could be wrong but that's my guessing, looking at the core front panel renderings. You can to remember, the SSD tray is probably only about 15-19mm tall I'm guessing, since most 2.5" SSD's are 7mm or 9mm tall, you're limited to that dimension behind the booster cell cover and the fans are going to be pretty darn tight against the flat surface of the core for a large portion of them. Hence why I believe if it were 92mm over each other, one would be practically useless.
I think this is also a good time to mention, if you plan on using a 120mm radiator in the front of the case, your airflow benefit from a booster cell might be a little bit less than you desire. I see the booster cell being most useful for fully air cooled systems with glass panels. Probably with the booster cell pulling in air, and the two other fans exhausting it (or vice versa).