Finally got around and through the topic, so yeah, late to the party. My 2 cents (haven't built a lot of wheels, haven't tested things out much, only thought some details through) and I think most of it has been covered as well. The wheel for sure hangs from the top spokes, no way around it. The spokes we use, the way they are laced, do not give a compressive support, so the bike is carried by the top spokes. What the bottom spokes do give is stability though. Spoke tension shouldn't give much of an impact on wheel stiffness...