Your 1:1:2 ratio is pretty close for the KAF0401E spectral response and the Astronomik filters. Though, doubling B compared to that of R seems a little excessive. I would suggest B be around 1.5
Personally, I would balance when combining. However having stated this, it is important to note that post processing colour balance isn't a substitute for lack of data acquisition. You should still take plenty of R, G, B exposures to improve your signal to noise ratio. Try to at least keep around the ratios for exposures, but accuracy is not needed when post processing colour balance is used.
The Astronomik LRGB type IIc filters are still considered broadband. By narrowband filters I mean specific emission line filters;
http://www.astronomik.com/english/eng_halpha6nm.html
http://www.astronomik.com/english/eng_oiii-ccd.html
http://www.astronomik.com/english/eng_sii-ccd.html