The bowed parts are not the problem here, since they - or at least most of them - are not off-key. In fact, they sound great, at least on my system (electrostatics with an excellent REL subwoofer). It's the first and last tracks where Kowald is "humming" (or should I say "growling") along and a few of the early tracks I'm having problems with.
Strange thing is, I like bowed bass much better in free / improv than in straight jazz. For instance, I can't stand Paul Chambers' bowed bass, which is almost always out of tune.