I put Sadowsky flats on my P5. They have a tapered B and sound great.
You should always set your "witness points" on all the strings at the saddle and the nut.
One more thing I found on my P5 was the nut slot on the B and E strings needed more taper towards the tuning post for a better break angle.
Check out Rodger Sadowsky's video "Behind the notes" on youtube.
He gives some great advice about setting up a bass.
That man knows how to make a 34" 5 string play and sound good.
It's 106 miles to Chicago. We've got a full tank of gas, half a pack of cigarettes, it's dark, and we're wearing sunglasses. Hit it.