What settings would be good for going from cRGB to sRGB?

How about from sRGB to cRGB?

FirstLight will display RGB black at 0,0,0 on an RGB display and 16/64 on a YUV device like over HDSDI/HMDI. If you are not apply LUTs, cgRGB to vsRGB and vise-versa can be done with Lift and Gain controls alone.

vsRGB to cgRGB
LiftRGB to -0.063, GainRGB to 1.164

cgRGB to vsRGB
LiftRGB to 0.063, GainRGB to 0.859

Then export as a LUT, so you can just apply LUTs to make this conversion.