Anthony, I used to set a custom white balance inside the camera before taking images then just stack them in DSS and fiddle them in photoshop once stacked. Ideally to take a CWB you shoot an image of a 'grey card' (purchased from a photo store) in full sun and set that as CWB. Normally I'd shoot a shot of a white sheet of paper in daylight and set that as CWB. If using any sort of skylight filter, you'd need to shoot a CWB with that filter in the chain.
When I say used to, I mean before the rain started last December
