Re: Metal humbucker for alder body / maple neck guitar. DD too shrill.
Does the FR1000 have a brass block? A big brass block can help add a little bass back into an FR system.
Electrically there's lots of stuff you can do to tame high frequencies in a guitar:
Tone pot:
- Turn the pot down.

Seriously. You would be amazed how many people set this to max and then never touch it again. A great many guitars sound best with the tone knob back to about 6-7 most of the time.
- Turning the pot down a bit the about the same effect as swapping 500k for 250k.
- Change the capacitor value. What cap value do you have there right now? If it's .047 uF, you might find it too dark to have much usable range on the tone knob. .022 uF is generally a good starting point for single coils and humbuckers. You might also try .015 or even as low as .010 to get usable tones all the way down the knob. The bigger the cap value, the more mid range your tone knob eats when you roll it back. The smaller the cap value, the more upper frequencies it gets rid of. Caps only cost a few cents, so it's worth playing around for an afternoon with some alligator clips to figure out what you like. If you're not regularly using your tone knob, you are using the wrong value cap in your tone circuit.
Volume pot:
- Changing the volume pot to a lower value will make pickups sound darker - less peaky/spiky. A 500k tone pot rolled back a bit so the pot reads 250k will sound just like a 250k tone pot at full. This is not true for a volume pot. A 500k volume pot rolled back to 250k will still sound brighter than a 250k volume pot at full. I find that volume pot changes make a big difference to the character of a pickup.
- If I'm playing with the value of a pot it's really helpful to get a bunch of resistors and use them to step the pot down in value.
500k pot in parallel with 300k resistor = 400k
500k pot in parallel with 100k resistor = 300k
500k pot in parallel with two 1k resistors = 167k
etc.
This lets you quickly figure out what value you like the sound of and is way cheaper than trying to source/wire in a whole bunch of different pots. I've found that dropping 500k down to 400k can transform a piercingly bright pickup into something quite pleasing.