I´m about to buy a dirtcheap 4x12 cab. it has celestion g12 50 speakers. gonna swap em out. im thinking about putting in two v30´s at 60w each and 2 greenbacks at 30w each. now i have the greenbacks in a 2x12 cab and im worried ill burn em when pushing my jmp mkii 50watter. so what i wanna know is how is the wattage distributed trough the 4x12 ? ? would it be safe or is my greenbacks at risk. they are from 1971 pre-rola g12H and sound amazing.