I ended up knocking off the nut the bass, and flat-sanding the neck to get a low, growling, jazzy action. They all come from the factories with a huge relief [bow] in the neck. I tacked 1.5 inch-wide, 50 grit emory cloth strips onto 1.5" by 5' aluminum "I" stock...and flat-sanded the fingerboard. Lots of experimenting with the string placement and height. A lot of trial and error. Almost perfect.
I also used dots of white nail polish to mark the the side of the fretboard to help me navigate ;^)
ps...TX wilco. It's the first time I've used 'bright ambience' for verb. It worked really well...kinda like a dance practice room in a factory loft. I like it!