Hmmm... I miss some clarity, which will be even worse with flatwounds I guess.
I posted this a while ago in another thread: I used flatwouds on my T-bird and the tone just died (Ask Basvarken), I used a flatwound P with flatwounds which was okay, but not that great.
A while ago I changed the strings of my Shadows Bass to normal roundwounds, while Burns UK advices to use flats. Man! That bass came to live immediately!! What a bass!