I use the gray card and CWB and I re-shoot the gray card after applying the CWB. Even though I do shoot RAW. Because I don't only take one shot of a scene, and my post workflow is sped up by getting the WB right on the reference shot and then applying it to the rest of the shots of that lighting.
In e.g. nightclubs where the lighting is all over the map I just use a fixed WB depending on the base color temperature of the colored lights. Those colored LED lights are ruinous to normal photography BTW, but a ~5000K WB can get you a basis point.