A 32-year-old woman with intermittent asthma uses salbutamol 100 micrograms per actuation via puffer as needed. Over the past 2 months she has daytime symptoms twice weekly and night-time waking with wheeze every 2 weeks. She has no fixed airflow limitation and normal spirometry between episodes. According to the latest Australian Asthma Handbook recommendations for adults, which is the most appropriate preferred reliever and controller strategy?