I think the original poster was simply saying that the amp was tweaked in the design phase with an N4 as the test guitar (since that's what Nuno plays). It only makes sense that they use the N4. Why would they use something else?. . .they aren't going to bring Nuno in and say, 'okay Nuno, today we're showing you where we're at with your signature amp, which will produce your signature sound. . .let us know how it sound to you -- now go pick up that Danlectro and plug in."
Sure there are lots of guitars similar to the N4 that would yield similar (if not identical tones). But they didn't use them when they were tweaking the amp.
