I was looking at how the Rickenbacker 330 and 360 guitars were built during the years. I noticed that during the '60, the body were made with 1/4" thick top and bottom and then reinforced with x bracing (first picture). Then some years later the top/bottom became thicker and the bracing disappeared, but the area around the bridge was not totally carved (second picture). Many says that the first example sounds more acoustic and more resonant (unplugged). I'm wondering if there is any technical reason to explain that. Afterall, both examples are semi-hollow constructions. Also, I'm wondering, for this kind of construction, would it be better to have a 2-pieces body (the two pieces joins only through the thin top/bottom area) or a 3-pieces body (when the pieces joins togheter though the mortise shoulders, so more glue area)?