The Dead are who I ended up "seeing" many times over the years buying tickets directly from them and ending up in the first few rows. Even with the center fill, or stage fill, whatever you call it, it was not like hearing and feeling the "big set". Their sound was really good (probably without equal)for those kind of shows while Healy was there. In front of the soundboard is definately a good spot.
And the triangle analogy is correct, just like at home, sitting at least as far back as the speakers are apart.