Measuring the decay to 0.01M 0 corresponds to a measurement time of t ≈ 10τ * (Fig. ), which is consistent with the calculated maximum recommended T 1 measurement time for non-exponential (i.e. stretched exponential) relaxation in solid state NMR measurements obtained from measurements of the 6H polytype of silicon carbide containing B, Al, and N. Using the M(t) ≥ 0.01M 0 decay traces, we now compare the options of fixed or free parameters in Eq. 11, along with all measures of τ (τ mode , ⟨τ⟩, e ⟨ln [τ]⟩ and τ * ), to find which combination provides the closest match to the waveform dataset (Fig. and Fig. ). All methods that allow free fitting of M 0 are generally in poor agreement with the waveform results, showing a downturn for most measures of τ at low temperatures or show wildly diverging values at high temperatures (Fig. ). Thus, M 0 should be defined by the first point in the target field and hence t offset should be set to zero and using Eq. 2 is sufficient; gratifyingly, this corresponds to the methodology employed by most experimental groups, including ourselves, to-date. As we only fit M(t) ≥ 0.01M 0 , then M eq should either be free or fixed to the target value (which here is M eq = 0 as the target field is calibrated to zero) and not fixed to the last measured point. Allowing M eq to refine freely