Pay attention that the NGK B7ES are long reach plugs that only fit if you happen to have KR heads installed.
For my stock KH NGK B6HS work well for in town and 55 mph cruising. They are equivalent to HD #3 which is what the factory recommended. For high speed operation B7HS would be your choice, equivalent to HD #4, again what the factory recommended for high speed. You might also find that best looking plugs are obtained with a #3 in the rear and #4 in the front, not unusual according to the Sportster book. It is what I am running these days.