G'day Suavi,
I recall from way back in 2012 there was a
processing challenge posted by Vicent on the PI forum. He had data from something like 23 images/filters. There were a few guys who posted their take, but the most in-depth was, not unsurprisingly, from Juan.
He posted a detailed breakdown on his approach. Not sure if it'll be directly translatable to your narrowband data, but might give you some ideas.
I also got to thinking about RGB vs CMYK. Perhaps you could assign a filter to the
CMYK and combine along these lines?