Again, @Boodang wrote some very good notes.
I want to add that as long as you use any passive, hi-Z components in between the pickups and the preamp, the response is sacrificed. Any pot, be it blend, vol, or tone, will degrade the original sound.
You want pure sound from the pickup, connect it directly to the preamp. You have two pickups, you should use some non-loading circuitry (Noll Mixpot or similar) between the two, or use two preamps, one for each pickup.