Well given I use Astronomik filters, I'll put in a plug for them.
I have the new low reflection TypeIIc series 50mm square filters in my CFW-5-7 on my PL16803 and so far I have seen no significant halos, in any of the images I have taken, nor out of field star flares with my AP152EDF which has a 4" field flattener to boot (my chip has the mask though) No halo removal has been done on any of these shots either:
http://www.pbase.com/strongmanmike2002/recent_images
There are some bright stars in some of these shots but a better test will come with the Orion Rgion and other "really" bright stars of course but then most filters have issues in these areas anyway from what I can see..?
Mind you the FLI CCD window is ultra low reflection too though ie > 99.7% transmission across visible wavelengths and virtually 100% transmission in the green. So don't under estimate this aspect of reducing halos.
http://www.pbase.com/strongmanmike20...99124/original
As far as colour balance goes..?...I haven't seen anything that would worry me
Just my 2c worth
Mike