1. Ignore the 53/11 advice, it's a joke.

2. Most REPUTABLE sources will tell you that a combination of standing and sitting is the best way to climb. When your sitting you want easy gears and a fast spinning cadence...when you stand for a short spurt, drop a gear or two for more resistance, but still aim for a medium cadence...if you are ever climbing at a low pedal speed, it should only be when you don't have any easier gears left.