Rick, the trims set your gains for each pickup which then combine that mix thru your volume pot.
Alembic classically places the two pickups near the end of the fingerboard and often right next to the bridge. Not only is there a tone difference, but a difference in volume due to the fact that the string is vibrating in a much bigger arc over the neck pickup (louder) than it is right next to the bridge over the bridge pickup (noticeably less gain than the neck pickup if the two pots are set at identical positions).
So since Spoilers don't have a pan pot, you set your 'both' pickups position tone on the rotary selector by using the trim pots to get a more twangy sound (back pickup louder) or a bassier sound (front pickup louder).
You can experiment with those gains, bearing in mind the difference you can live with when soloing either pickup if you play that way.
And your pickup heights will affect tone and volume a little. These are low impedance pickups, so typically they aren't as 'spike-y' regarding pickup heights but you will hear a difference as you raise or lower them.
And remember the Alembic pickup adjustment drill: Loosen the two screws you can see, then reach through and adjust your heights with the two screws you can see through the other two holes. When you get them where you want them, then just snug up the two screws you can see. Just snug, NOT hard tight, snug is enough.
You can experiment endlessly with these adjustments if you can truly hear the tweaks: Some can, some don't. And there's no 'right' answer, just set it where YOU like it.
I'd also recommend doing this with new strings, they will be the most honest in what you're hearing, and you can avoid a few aural mirages that old strings can sometimes supply . . . .
Joey
