Table 3.17D in the Wood Frame Construction Manual provides maximum shear wall segment aspect ratios for various wood and gypsum assemblies. Also see Special Design Provisions for Wind and Seismic Table 4.3.4. Typically, 3.5:1 is the maximum aspect ratio for design of blocked wood structural panel shear walls. For an 8′ tall shear wall, that would mean 27-1/2″ of full-height sheathing.