This started because I have a bolt-on Epi T-Bird here, and didn't like the sound of it at all. Not one bit. Just the most 'bleurgh' sounding thing. (apologies for being so technical) so I did the thing with the 2 j-pickups, a roll of insulating tape and a push-pull volly pot just to see what would happen.
Mercifully explosion-free, the experiment was a resounding adequate. I really liked the sound of this in single-coil, proper old-school, fat and aggressive, just like me.
In humbucker it sounded pretty much like any other 'bucker out there.
This was in the neck position. I thought if I liked it enough, I'll look for ways of acquiring more pickups for the bridge, and of doing it without tape! In the meantime I decided to put the bass back together while I wait for that to happen, but in doing so I seem to have repaired whatever the hell was wrong with it in the first place, sounds good now, so the plot with the pickups goes in the 'hare-brained schemes pending' file.
Never did get round to trying them the opposite way round after all, that being the whole point, like!