Request: Gamma 2.2 Preview Mode

I've been working on getting accurate chromaticities on DSOs captured with my well-calibrated stock DSLR. Accurate display of the linear color-matched data requires gamma correction, which I do with pixel math (output = input^(1/g)). However, none of the Display Modes simulate the typical screen gamma of g=2.2, so I have to edit in the blind until the very end. The closest is Square Root (technically, g=2), but it would be nice to have a g=2.2 mode. An sRGB stretch (slope=12.92, gamma=2.4) would be gravy.