i see EXACTLY where you are comming from on the t-bar thing(in my head it makes sence to me as well), BUT when you crank the t-bars the ride is firmer. i can say that without any doubt. i know this is true on my 90 4runner. when i crank them up the ride is rough as hell with the 25mm t-bars, when i let them down, the ride is softer with the same 25mm t-bars.
i can also give an un-biased opinion. my dad has an 87 4runner. he put 32's on it and said the tires rubed a little up front, i told him i would take care of it. well i cranked the t-bars one weekend and sure enough "what did you do? its stiffer now".

cranking the t-bars does make the ride stiffer, im almost positive i cant be convinced otherwise. cranking them may not change the spring rate, but it makes the ride stiffer and the angle on the a-arms could have nothing to do with that.