Well said.You can't EQ a Jazz like a P bass or a Warwick. J basses have naturally scooped mids, some folks are looking for that sound, slappers for instance need the mids cut to keep from being harsh, depending on the tone your after and your technique, your amp settings need to be adjusted accordingly.
You can't just expect to pull the plug from your P and plug in your J and have the same place in the mix.
I usually favor the neck pickup just short of full on when I play my jazz. When I want a P bass sound that really cuts through I use a P bass.
Sorry, I didn't read thru all the pages but hopefully you figured it out.. Just play your P bass.