How low did you adjust the pickups? I still think that's the biggest part of your problem. The volume drop off is normal but can easily be compensated for. Also, get yourself a good overdrive pedal. That way you can play at very low volumes and ditch the need for headphones.
This will also allow you to choose the best amp for you without a need to only choose from amps with a headphone jack.
This will also allow you to choose the best amp for you without a need to only choose from amps with a headphone jack.