Most fly fishermen are catching about the same as you. While there are large stripers throughout the Northeast during the summer, they are usually deep or scattered. I think your best shot at a big striped bass would be in two areas not usually considered by New England fly fishermen. During December and often in January (weather permitting), large stripers are often encountered in relatively shallow water at the mouth of the Chesapeake Bay at Virginia Beach and on the Outer Banks of North Carolina near Nags Head. Both areas have guides that cater to fly fishermen.