Interestingly, I, being a hardcore Roto and Blue Steels user, have really been digging Fender flatwounds on my SI of late.
I'm using the 45-95 set, and they give me everything I need/want for Rock to Blues to Jazz. I don't pop with them, though, as they just don't sound good doing that, but really for everything else, I'm sold.
Also, I've been playing bass from the soundboard quite a bit lately, and the flats make it much easier to fit the instrument into the mix without having to EQ-out all my definition..
My bridge filter stays put in about the 1/3 open position, volume full. Neck filter is about half-open, volume 3/4. I mostly am getting my tone changes from the bridge Q-switch and tiny tweaks to that filter.
And they're cheap strings, which means something to me these days!
John