Oh wow, boy did I screw up.

The Bare Knuckles are good, very good really...but not as good as the Duncans I had in it.
See, I didn't wait until I was done tweaking on the SD Custom 90 before I ordered the BKs. I didn't mention it (I don't think) but when I swapped the ceramic magnets for the A5s...after a couple of days I started to get annoyed with the lack of mids and kind of a hifi thing it had going. So I swapped the the mags again for A2s and that was what I was looking for, but I think by then I had already ordered the BKs.
The BKs are good, they're fat (as described) and Maybe too fat on the bridge pickup. It works great for high gain chugging, but it lacks the definition and articulation the SD has and that's the part I love most about P90s. I'll give them a little more time, but I think the Custom P90 is going back in. I'll try it with the BK neck pickup because it might be better than the SD neck, but if it's not RWRP I won't leave it.
I sure do stupid things sometimes and I waste money every time..
Now for the good news! The RS wiring harness is great!! The pots feel great, they're stiffer and don't spin loose like the stock ones, the shafts don't wiggle anymore and the tone pots work thru the whole taper now, yay!
I took note of what
@Don O said in
@Jethro Rocker 's soldering thread about never soldering the back of the pots. Since I forgot to put a note that I didn't need the ground wire connecting all the pots when I ordered because I had a metal control plate and it came with the ground wire already soldered to the pots and I just took advantage of that. I unsoldered it from the tone pots, but I snipped it off and left enough of the wire still connected to the volume pots to put a little loop at the end to solder my pickup grounds to without having to heat up the pots. I've burned up a lot of pots over the years so I don't know why I haven't thought of this before. Now if I want to swap pickups as many times as I want I won't ever have to solder directly to the back of the pot. I just soldered the bridge ground to the same spot on the neck tone pot where I removed the ground wire so it's out of the way.