Extrapolation of static test results to seismic design has to be performed carefully. The principal response quantities for static loads (for structures, wind load is regarded as static) are strength (measured by total applied load) and stiffness (measured as the ratio between applied load and deflection). Under seismic load, energy dissipation is the key response parameter. At this point, I don't believe that anyone has any energy dissipation data for western style timber frames. Some research has been performed on Chinese and Japanese frame types.
I'm reluctant to predict or recommend an R value for traditional timber frames. It is certainly easier to direct all of the seismic load into shear walls or SIPs, when those load paths are available. Behavior of a stand-alone frame during a seismic event is yet another question.
For SIPs attached to a timber frame, I'm comfortable using load-slip data from our research at UW and designing as if a single skin of OSB (the inner skin attached to the frame) is active in resisting load.
