I use hutech lps2 for all my city based imaging both for Dslr and ccd. I have not yet reached sky glow at 10 min subs. The best way to judge is to look to the spectral graph. If you look at the lps2 you note that it is very narrow in it's blocking of the worst types of light pollution whereas other filters overlap into the wavelength you want to preserve.
Here is a link to the graph
http://www.sciencecenter.net/hutech/idas/filtdata.htm