(A) Traditional 3Q methyl relaxation experiments (Sun et al., 2011) involve collecting matched pairs of allowed (SQ) and forbidden (MQ) spectra at several relaxation delay times, calculating the ratio of peak intensities, and fitting the buildup to a function of η, the difference between fast and slow R2 relaxation rates. (B) Due to short lifetime of A2AR samples (~12–14 hr at 30°C), the experiment was modified to reduce number of forbidden experiments, which have very low signal-to-noise and accordingly require long collection times. To do so, we evaluated alternatives requiring the collection of fewer forbidden spectra (down to the limiting case of a single spectrum), allowing for more scans for that time point. The decay in allowed spectra intensities was fit to a function of the fast and slow R2 rates, and the one calculated forbidden:allowed ratio to the same function of η. (C) A relaxation experiment with allowed and forbidden spectra at five relaxation delays was collected on MBP andη values were fit from forbidden:allowed ratios at all time points. The plot showsη values for each peak in MBP fit from forbidden:allowed ratios at all time points and three selected combinations of limited timepoints. η values calculated using the ratio at the single 8 ms time point show good agreement with the comparable values collected using other strategies, but can be collected in less time than the ones requiring two timepoints. (D) Plot of the sum of squared differences between η values calculated using ratios at all timepoints and each combination of limited timepoints. The two combinations of 2 time points giving the lowest error, and the one single time point giving the lowest error are shown in blue, orange, and green respectively.