"Calculate wall seismic force, using the dead load of the top half of the wall (Chap. 3). Using the top half of the wall follows dynamic theory. Some designers use the entire wall dead load (conservative)." - page 10.15
"Use of 3X framing is highly recommended anytime the tabulated ASD shear capacity exceeds 350 plf. Shearwall testing has identified the splitting of 2X studs at abutting panel edges as a weak link in shearwall behavior." - page 10.17