hey Tim,
you actually lose that growl quite a fair bit, but to save it from dredging into dubby mud, my tone is on 10, and i tweak the treble EQ to get just the right amount of bite
but fundamentally, its an all new tone, rather reminicent of James Jameson, or playing palm muted..
i can't get Ben Kenny's tone.. i think it's also how the band plays around him or how he plays around the band, but in most situations, i find my flats getting masked if my band mates have too much drive going on.
it works with my Leeson stuff, although i switched back to rounds on my P recently, more tonal variation
but if i want that nice Fleetwood Mac-ish thump, something more vintage-y or mellow, i'd still pick that Jazz up..
hope that helps -)