One trick for the weaker climbers in a group is to move near the front of the group near the start of the steeps and allow others to pass you as the climb continues. Another trick is to shift up two gears just before you stand and pedal. It helps maintain speed. On short steep hills, select a gear that allows you to spin around 100 to 110 and that you can also maintain at 70 or so over the top. That way, you can stand and power over without having to sit and shift.
Higher cadences are also less stressful.
Lab research says that optimum spin rates for efficient pedaling are between 70 and 80 - the racers like to have much higher spin cadences as a general rule. No real answer - but it is probably good to have power as well as the ability to spin rapidly and smoothly and then find a spinning rate that works for you. On gearing and spin rate, you have lots of choices. If you prefer to spin fast, you can gear down and go fast. If you prefer to spin more slowly, then you will want to push a bit bigger gear.