I play a '76 Precision thru a GK 800RB with 2 10" Celestion and a 15" Black Widow. Anytime I set the volume knob above 12:00, maybe 1:00, I start worrying about blowing speakers. Would adding more speakers to the equation help? Not looking to double my volume, just 25% or so more sound. Oh yeah, there is an open jack on the head. Thanks for any advice.