I sail out of the Patapsco and go to Swan Creek at least once a year. I line up those range lights and follow them across the bar, even at low tide. I've never had a problem and I sail a winged-keel boat that draws 4'2". Seems to me that the area "safe" for crossing is rather large because lots of folks have their own theories and they all seem to work.
How close to you stay to range lights? Do you stay inside the "cable area"? I have a 4' draft also, but still feel uneasy about getting stuck out there so I opt to go around. Its not like grounding in some creek where you have some protection, you'd be out there pretty far "high and dry" so to speak. I'd hate to ground out there and get hit by an afternoon t-storm. However, if I can cut 3 NM off the trip that would be a good thing.