Fret not, the man in question was requested to feck right off and buy me a pint of guiness before the rest of the band ate him (and they looked like they could).
The way I see it, I was pushing the Life out of the laney, and a Marshall half-stack would have needed turned down. The P-90's made the sound more attacking and distinct, and (most importantly) the other guitarist was using a Marshall Half Stack and a Les Paul, so another would have just sounded like bassy, sludgy soup (LP's don't take downtuning very well, in my opinion).
By the way, anyone finding their sound a bit bright should maybe check out a bass cab as an extension. Adds a lot of moving air. But I wouldn't say it was the only or "right" option ;-)