If I were building a motor for a tow vehicle I might use a dual plane. For any performance build I would always go with a single plane. I sure wouldn't put a dual plane on a hemi. As far as the magazine story I wouldn't put much faith in their findings. Some of the things they do in magazines boggle the mind. I have a Barton Intake and I am very happy with the performance. If you can fit it under the hood it is a very good intake.
I have never seen plugs so Identical as the plugs in my hemi.
Every plug burns the same.
Since this is my firts hemi I thought it was the nature of the hemi but it sounds like the intake might be responsible.
The only thing more risky than using information from a magazine article is asking for advice on the internet.