What is the difference between Nitrous Express Stage 6 and Gemini Twin Stage 6 kits?

Hello,
Does anyone know the difference and application between the Holley Conventional Stage 6 (50-300hp) PN: 30040 and the Holley "Gemini Twin" Stage 6 (50-300hp) PN: 60040? The only difference that I know of is the plates are different.

Here is the link:

http://www.nitrousexpress.com/Pages/HolleyGas.htm

I called Nitrous express and here is basically what they told me:

The Conventional Stage 6 uses the plate that has the spraybar down the middle. The Gemini Twin Stage 6 uses the spraybarless perimeter plate. That is the ONLY difference in the kits. Everything is identical.

I am sure both work fine, but I have gotten conflicting tech support from Nitrous Express on which one to get. Some say that the perimeter plate is ONLY for single plane manifolds, and to use the plate with the spray bar for dual plane. Another tech told me the exact opposite. I have a Edelbrock Performer RPM Air Gap manifold. I buddy of mine has the exact manifold and he has the perimeter plate and swears by it.

Anyone have any firsthand knowledge of which one I should get?

Thanks,
Jim