The Alnico II Pro pickups are very nice but I don't know if I would consider them "metal" pickups.
Now this is simply my opinion, don't lynch me. I've had very good experiences mixing bright amps like Marshalls with dark guitars / seymour duncan humbuckers. Generally the thicker woolier tone really gives a lot of girth and chunk to the more brittle and defined tones.
My love affair with Bare Knuckle pickups is that they mate so incredibly well with Mesa Boogie amps, amps that start to quickly become dark and muddy with dark guitars / seymour duncans. The clarity and detail really contributes to the overall tone of a boogie which is also very detailed / complex.
So, consider your amp. For Metal / Non metal, I think it's more an amp thing. I discovered that Nailbomb + Les Paul + Dual Rectifier = really modern tones. Electra Dyne + Les Paul + Nailbomb = wicked warm (Brown) and more vintage crunch tones.
Marshall JCM 2000 + Mahogany guitar / Bolt On Neck (Godin LG) plus Custom Custom in the bridge = wicked thick and bright metal tones and killer rock crunch.
Oh, Rebel Yell set is also awesome. It can do metal like tones but it's different than a Nailbomb. More mids, more open highs, and cleans up even better with the volume pot.
Maybe try recording your guitar unplugged to get an idea of its overall tonality? I've been doing this now to help with my pickup selection.
Here is my document for reference. #1 Godin LG. Very scooped guitar with really phat low mids and a bump in the low treble / high mids around 4 - 5k.
Mahogany neck bolt on, rosewood fingerboard, mahogany body.
#2 Gibson Les Paul. A thick but clear lows, more than adequate low mids, a present, round midrange up until abound 2k. Very even high mid and treble response.
Mahogany set neck, rosewood fingerboard, mahogany weight relieved body with a maple cap. This guitar sounds much like an acoustic guitar unplugged.
#3 Godin Redline. Hard maple neck, rosewood fingerboard, soft maple body with poplar wings. Bolt on neck. Big lows and low mids but definitely much more mids, especially 500 - 1000Hz. A bump between 3 - 4k. It's strat like, brighter than the other two guitars, but very balanced. Dark for a strat.
#4 Peavey Predator AX. Strat Copy. Maple neck, rosewood fingerboard, bolt on neck. Not sure what the body is, but most likely poplar, alder, or swamp ash. This guitar was the brightest for sure, with a lot more mids than the other guitars. The upper harmonics were particularly present, from about 6k up to like 10k.
I recorded these samples with a condenser mic around the neck pickup on the instrument. This little experiment has been really helpful for me when I was attempting to choose pickups.
Happy choosing.
