Usually the most sensitive loop is placed at or just behind the stop line and additional loops farther back let the system know that multiple vehicles are waiting. So I'd stop and place my bike for best detection over the loop closest to the stop line in the appropriate lane. Report it if it fails to detect you. The more such reports they get from cyclists the more likely they are to adjust the sensitivity on the detectors to change the lights for us. In our area they're pretty good about responding to complaints, but it would be better if the sensitivity were set properly to start.