When I had the house built, I had the contractor add 3 feet on to the back of the garage on run a vent up through the roof. Same as the kitchen exhaust vent over the cooktop. When we picked out appliances I bought two kitchen vent hoods, dual fan, 3 speed high cfm jobs. Built my loading/casting bench in the 3 foot extension of the garage and installed the exhaust hood at one end of the bench. Works great no matter how smoky the flux is, no smoke and barely any smell in the garage.
The old house, I did the open door with fans behind me and in the door. Yeah it sucked out the smoke, but not until after I sat in the cloud for awhile. It's a grand denial thinking good ventilation is being paranoid.