From memory we used 42 NEDW#2 175/178 in the local dealers demo 15 250R. Seems to run well, but I haven't rode it much more than a lap around the block. He reports good running and great fuel economy on it.
The 300R he sold was super thirsty and the Suzuki needle didn't show much improvement. They had not set the floats though, and I haven't heard back since offering some advice so I assume the owner has it running much better.
Based off what you describe, the logical choice is to drop the main several sizes. The JD needles run a lot leaner towards WOT (and JD generally recommends richer mains than OEM to compensate), although you may find dropping the mains down will result in the bike wanting a richer clip position too.
I also know, on some bikes that Dave at TSP has had on the dyno he's been able to drop the mains down into the mid to high 160's, but that's on a modified head, tight squish, and usually 300cc.
I'm running 40 NEDW#2 175 in my 250, and don't have any breaking up anywhere. It can feel a little lean in the mid at times, but the piston wash shows slightly rich, the plug looks good. I've considered going half a clip richer and possible dropping the main a size myself. Of course on a 13 with modified head, working in a tropical climate (mid 20-30s celcius, humidity generally above 50%, and some elevation too).