Big Block muffler choice

I have used hooker aeros, long magnaflow straight thru, and giant flowmasters. The FM I'm using won't fit under an a-body, but I really like their sound the best (3 chamber, 5x12, 28"oal, 22 case. ) The aeros being a chambered muffler sound similar.
My theory for a quiet efficient exhaust is: get the right size pipe for the engine, and as big and long a case that will fit under the car.
In your place I would try dynomax or magnaflow straight thru, with the longest case that will fit.