double brake? you mean squeeze one handle and it engages both front and rear brakes? I'd like to hear more about that. I am riding with only rear brakes
I can testify that the factory dual pull style like cruiser posted are not ugly and they work great. I've been using mine for months.
I rigged the front to the inner most pull and the rear pull to the outer. Pretty easy to adjust for perfect balance. Your variety of hand lever may not accommodate the Ghost0 2x pull.
Found a good way to get off old hand grips, just slide a thin long screw driver between the rubber and handle then lift slightly and spray WD40 in with the tube attached to the nozzel. The grip will slide right off.